African Tiger Fish (Hydrocynus) ID and Care Guide 3.0

[Chicxulub]

A Guide to the Care and ID of African Tiger Fish (Hydrocynus) 3.0

2.0 update- complete rewrite for both readability and depth of information.
2.1 update- minor updates to Suggested Reading.
2.2 update- Sweeping format changes, updated data that's recently become available, reduced image count to help load times.
2.3 update- Minor format changes for readability after the migration and a new blurb about BATF.
3.0 update- Nearly complete rewrite updating the Guide after four years of inattention. Added cf. "stout vatf", cf. "big eye", updated the rest of the species profiles, updated husbandry, fixed links. Need to find and re-upload Photobucket pics.



Table of Contents, Introduction & Acknowledgements

Table of Contents

NOTE: Click on the hyperlinks to go to that content.

Introduction, Acknowledgements & Suggested Reading
General Care
Key to Species
Hydrocynus goliath
Hydrocynus brevis
Hydrocynus forskahlii
Hydrocynus vittatus
Hydrocynus cf. "stout vatf"
Hydrocynus cf. "big eye"
Hydrocynus tanzaniae
References​

Introduction

Greetings again!

In the four years since this guide was published, many things have changed. I have finished my education and gained lots of real world experience working as a fisheries biologist. Even more importantly however, we as a community have gained four years of real world experience with these animals, which has gone a long way in helping to elucidate the reality of these animals: both their husbandry and their taxonomy.​

Acknowledgements

I would like to first thank everyone who has done work on these fish before me. Your hard work and dedication has been essential for me to be able to compile this information. I don't pretend to be the progenitor of this information; I am merely compiling the data that is a result of years of research and work into one place.

I would like to thank everyone who has put up pictures that have found their way into the public domain. I spent hours scouring Google to find pictures to help to illustrate the points I wished to make. I made sure not to use pics that were copyrighted or that I was specifically instructed not to use. Shame, that; I am not authorized to use the finest picture of a brevis that exists. If you see your picture on here, let me know and I'll mention you in this acknowledgement section as a contributor. I know probably more of these pictures than not belong to members here. I'm not trying to steal your intellectual property, I am merely trying to contribute to the community. As such, all rights to all pictures belong to their owners and are used under the fair rights principle. If you don't want me using them, I will remove them. Thank you.

I would also like to specifically thank these MFK members-

Tigerfangs, whose wonderful pictures of his fish from some of the first batches to be imported were a significant inspiration for me to learn about these fish, and whose sage advice regarding the care of these fish still proves to be true to this day.

DayumDanny, who jumped into helping me prepare this thread with both feet. He was wonderfully helpful with compiling pictures for the galleries.

And finally a man who has played an immense role in bringing ATF into the hobby, Mr. Rare Fish himself, fugupuff . Without Wes' help, this thread would not exist. Wes' help is also critical to helping me continue to learn and grow about this genus.
​

Suggested Reading

In this section you will find influential and important posts and/or discussions that happened on MFK on the subject of African tiger fish.

A Definitive Key to Identify African Tiger Fish (Hydrocynus) (Version 1.1 of this guide)
On the problem of identifying African Tiger fish and the mythical Black Goliath.
Hydrocynus sp. Tiger fish clarification
Show us you Goliath Tiger Fish
SHOW YOUR ATF
TATF, VATF, Lake Tanganyika, exporters and why you don't know what ATF you have
Big Eye ATF ID definitive proof... TATF!
Another ATF riddle solved. Brevis & Forskahlii; same tank, same time. How to ID.
An interesting article on ATF
Bloat in Goliath Tigerfish​

 

[Chicxulub]

Chicxulub's Care Sheet for Hydrocynus

General Housing Requirements

It has been said that African tiger fish are a very difficult group of fish to house in an aquarium. While not exactly true, it is fair to say that in order to thrive, they need a very specialized environment and, as adult, a very large home. As such, if you intend to keep an ATF for life and provide for its needs correctly, you're going to have to be prepared to make a considerable investment of time, money and resources. However, if the fish's basic needs are met, you will find that your new tiger is a very hardy, low maintenance fish.

In the wild, ATF are exclusively restricted to warm, well oxygenated fast flowing rivers and areas of large, open rivers and lakes that possess extremely high dissolved oxygen content (Goodier, Cotterill, O'Ryan, Skelton & de Wit. 2011). One has two paths to choose when providing for these fish; you must choose to emulate one of their preferred habitats. It is advisable to provide current for the primarily riparian species (GATF, VATF, TATF) and good oxygen for the primarily lacustrine species (FATF, BATF). Of course this is just a suggestion, and all five species can be found in both habitats.​

The subject of precisely how to provide the current is probably the most common question I have received. If you choose to go this route, the current cannot be violent and arbitrary. You must ensure smooth, consistent laminar flow (wikipedia) moving from one side of the tank to the other. Providing flow that is nothing more than turbulence will only stress your fish.

Whichever husbandry technique you choose to use, it is important to note that an easily startled young ATF in too large of a tank can easily accelerate sufficiently to cause permenant damage or death upon striking the glass at the opposite end of the enclosure. As such, I have found good luck in using smaller tanks that prevent the fish from going so fast. I also highly recommend using dither fish. Young ATF are a schooling fish that tend to live on or near the littoral shelf in their home waters and are highly vulnerable to predation. The presence of confident happy dither fish helps the ATF remain calm. Unless you've got very deep pockets, it is best to use cheaper dithers as a love tap from an ATF can be fatal to similarly sized tank mates. I recommend tinfoil barbs at a rate of three barbs per ATF within reason for the size of the tank.

H. goliath - 8x4
H. tanzaniae - 8x3
H. vittatus - 8x3
H. brevis - 8x3
H. forskahlii - 8x2
​

H. goliath rarely exceeds two feet in aquaria. VATF, TATF and BATF rarely exceed 18 inches. I have never seen evidence of a forskahlii being kept at over a foot in length in captivity. There are some fish that are documented as having exceeded those lengths, but they are rare and should be treated as the exception and not the rule. If you manage to even get your fish to those lengths it would have required an investment of years and you have accomplished something very special indeed. It is possible that you could exceed these sizes however, especially with goliath, and if you do you need to be prepared for that fact, unlikely though it may be.​

[
An enormous Hydrocynus goliath, courtesy of WU CHUN.​

Feeding

Based on the diet of wild ATF, I feel that it is absolutely essential to transition your ATF off of live as soon and as young as you possibly can. To do so is to take advantage of the natural inclinations of the fish. A study by Gagiano (1997) showed that in various populations of tigerfish, the young all tend to transfer to a primarily pscivorous (fish-eating) diet by the time they are 50mm in length. Before they reach that size, the young fish are primarily inclined to live in the shallows and eat insects and occasionally seeds that fall into the water. Adult fish will continue to take insects and seeds throughout their life, but only in circumstances of extreme duress where fish forage is not available.

Due to this change in behavior, it strikes me as opportune to take advantage of a very young ATF's inclination to eat from the surface. A method that I have had phenomenal success with is using tinfoil barbs as teacher fish. Read more about my method here. It is fair to note that your ATF may fight with the barbs. There is also a chance that the barbs may in turn rough your tiger up, but don't worry, he'll heal quickly. ATF, especially young ones, normally quarrel with each other anyway, so this simulates normal behavior for your fish and won't overly stress it. There is also a good chance that your young ATF will end up slaughtering a barb before it decides to eat pellets, especially if it is a larger specimen and is used to eating fish.​

A video showing young ATF who are undergoing pellet training.​

Furniture

For an ATF tank, furniture should be kept to a minimum. The more you put into their tank, the more you have for your flighty torpedo to impale itself on. Furniture will also strongly affect the flow in your tank, which is not desirable for the reasons discussed above. I personally prefer to keep them in a bare tank as I feel that the fish themselves are impressive enough to more than make up for the lack of decoration. The majesty with which a large, healthy apex super-predator such as an African tigerfish presents itself is something that truly has to be seen to be appreciated. If you choose to decorate your sufficiently large African tiger fish tank, a low profile 3D background and a river stone substrate would be attractive without the risk of causing undue harm to the fish. Large pointy driftwood and similar items upon which the fish could be impaled are strongly discouraged. ATF are also capable of a sufficient turn of speed in order to be killed by running into the glass. Should they spook and run into a pointy piece of driftwood, the results could be catastrophic.​

Compatibility

African tigers are hard fish to have as cohabitants with most other species. The most obvious issue you will run into is the specialized needs of the ATF. Most large fish that would seem to be compatible will not appreciate the violent current that the tigers require. Fish such as arowanas are a prime example of this. Another issue you will run into is the fact that ATF are very slow growing fishes. Most of the fish that would seem to be compatible with them will outgrow and out compete them very quickly, and in many instances even eat them. There are many, many confirmed instances of an ATF being eaten by a much faster growing tank mate on this site. A prime example of this would be, again, an arowana. If you were to acquire a six inch aro and ATF at the same time and grow them out together, by the time the tiger is nine inches, the arowana could be pushing fifteen. Remember now that while six inches is a common size for an aro, it would be exceptionally large for a new ATF purchase. You can see how this could become a problem...

Brevis has a reputation as being very aggressive and capable of damaging other fish, often more so than its congeners. This is due to an unusual feeding method as described by Lewis (1974) which states that brevis, uniquely among the African tiger fishes, routinely feeds on fishes larger than itself. The brevis will attack a larger prey item by targeting the back third of the prey fish’s body in order to amputate the tail. Once the prey item is incapacitated and has floated to the surface, the brevis will eat the prey item at its leisure by taking bites out of it. Caution should be exercised when housing brevis with other fish. The author can testify to the fearless, bold nature of Hydrocynus brevis. He kept a young specimen that was singularly fearless; this species is easily the boldest and most aggressive species. The author's six inch BATF would terrorize his foot long GATF.

An incredibly bold 6" BATF hand feeding. Courtesy Chicxulub.​

Fishes that work well with ATF are other large, slow growing, current loving fish. Tarpon, payaras, mahseers and large barbs are examples of fish that have proven to be compatible. Bottom dwellers are fairly easy, but you should wait until your tiger is about eight inches to add them to reduce the risk of the ATF getting eaten. ATF tend to completely ignore bottom dwellers, so your primary concern should simply be to ensure that the bottom dweller is a slow grower that will not eat the tiger. Tigrinus and juruense catfish work very well as do bichirs.​

Introduction, Acknowledgements & Suggested Reading
General Care
Key to Species
Hydrocynus goliath
Hydrocynus brevis
Hydrocynus forskahlii
Hydrocynus vittatus
Hydrocynus cf. "stout vatf"
Hydrocynus cf. "big eye"
Hydrocynus tanzaniae
References

 

[Chicxulub]

Key to Species

Click on species name to go to that profile for further details on that species.​

Valid Taxa

Hydrocynus goliath-
Usuallly with 12-14 teeth in the upper jaw. Gill rakers very short, less than one-third the length of the filaments; lateral line with 53-58 pored scales; anal fin with 3 soft, unbranched and usually 14 branched rays; vertebrae 52-54; lateral stripes not distinctive; found in the Congo river.​

Hydrocynus brevis-
Gill rakers approximately one-third the length of the gill filaments; 4th infraorbital width broad, approximately 7.7 percent of the standard length (range 6.9-8.9 percent); body deep; lateral line with 47-55 pored scales; vertebrae 49-51; lateral stripes conspicuous; found from the Nilo-Sudan region to the west coast of northern Africa.​

Hydrocynus forskahlii-
Gill rakers long, approximately equal in length to gill filaments; 4th infraorbital width (widthe of head just below eyes) approximately 6.1 percent (range 5.1 to 7.5 percent) of the standard length; body not deep; lateral line with 46-53 pored scales; vertebrae 45-51; lateral stripes prominent; found in the Nile, Sanaga and Omo rivers and western Cameroon.​

Hydrocynus vittatus-
Gill rakers approximately one-third the length of the gill filaments; lateral line with 45-50 pored scales; vertebrae 48-50; anal fin with 3 soft, unbranched and usually 13 branched rays; lateral lines distinct to pronounced; found widely throughout Africa in the Congo, Zambezi and Okavango rivers, coastal river systems south of the Lower Zambezi and in Lake Tanganyika.

Hydrocynus cf. "stout vatf"-
Not formally described. Broadly matches the overall appearance and published description of H. vittatus sensu stricto, but with 3-4 scales between the lateral line and the pelvic fin insertion and often fewer lateral line scales than H. vittatus s.s. Possibly corresponds to genetic lineage B, C or D from Goodier, S., Cotterill, F., O'Ryan, C., Skelton, P., de Wit, M. (2011). Known from the Congo watershed, exact location unclear.

Hydrocynus cf "big eye"-
Not yet formally described. Has coloration identical to Hydrocynus vittatus. Often develops very pronounced points on the caudal, anal and pelvic fins. Has a distinct pointed head structure. Scale counts match those of H. tanzaniae, with 43-47 lateral line scales and 3 scale rows between the lateral line and the pelvic fin insertion. Found in the Congo river proper, often caught as contaminants with Hydrocynus goliath.​

Hydrocynus tanzaniae-
Gill rakers approximately one-third the length of the gill filaments; lateral line with 43-47 pored scales; anal fin with 3 soft, unbranched and usually 12 branched rays; vertebrae 46-47; lateral stripes distinct; confined to eastward flowing rivers of Tanzania.​

Image credit to Goodier, Cotterill, O’Ryan, Skelton & de Wit, 2011.​

Invalid taxa

Hydrocynus vittiger-
H. vittiger was originally described by Boulenger as H. vittatus, but had to rename it due to the existence of H. vittatus that we are familiar with in the hobby today, which was already described and named by Castelnau in 1861. As such, Boulenger renamed what he believed to be his new taxa H. vittiger in 1907. H. vittiger was examined by Brewster in 1986 and found to be morphologically identical to H. goliath, which makes H. vittiger a junior synonym and confirms H. goliath as valid.​

Hydrocynus somonorum-
H. somonorum was described by Daget in 1954 on H. brevis material. It was described as being a separate species based on morphological variation within H. brevis. This species was rejected as invalid in that the supposed differences fell well within the described perimeters for H. brevis. As such, H. somonorum is a junior synonym of H. brevis, which remains valid.​

Cryptid

Hydrocynus cf. black goliath-

H. cf. black goliath is a proposed morph or species of ATF that supposedly lives in the Black River tributary to the Congo. These fish are highly sought after by hobbyists but are not currently imported. They are currently not described by science. These fish exist in highly acidic, dark, heavily tannic blackwaters. This condition can be replicated in the home aquarium with extremely heavy peat filtration, but the color goes away within several days of returning to normal water conditions.​

​

Introduction, Acknowledgements & Suggested Reading
General Care
Key to Species
Hydrocynus goliath
Hydrocynus brevis
Hydrocynus forskahlii
Hydrocynus vittatus
Hydrocynus cf. "stout vatf"
Hydrocynus cf. "big eye"
Hydrocynus tanzaniae
References

 

[Chicxulub]

Hydrocynus goliath

Goliath tigerfish, courtesy of C Chicxulub ​

General Info

Hydrocynus goliath is the largest species of ATF and the one that most people go searching for when they first try to get one. These things have attained huge popularity thanks to their inclusion in an episode of River Monsters with Jeremy Wade. These are probably the most sought after species, and as such are the most misidentified species. This is because the shippers in Africa know that goliath fetches the highest prices and often willfully mislabel their fish as goliath when they know full well the fish aren't actually GATF. Distributors will then sell the fish as whatever their distributor tells them it is, which invariably confuses the customers.

There are three apparent varieties of Hydrocynus goliath in the hobby. A faster growing population that is thicker bodied with a longer, flatter dead; a slower growing variety that is thinner bodied, more torpedo shaped with a more conical head; and a rumored black variety. There are credible reports of all black GATF existing, but are exceedingly rare. Based on my conversations with Douglas Dann in 2013, it appears as though the greatest preponderance of black GATF came from what he called the Black River in the war torn region between the Democratic Republic of the Congo and the Republic of the Congo. The increasing political unrest is why he left the country, and could explain the lack of black specimens in the hobby.​

Distribution

-Congo River and tributaries​

Diagnostic Traits for Hobbyists

-Silver
-Very little or no striping
-Tan, brown or rusty colored fins
-Bottom lobe of caudal fin red generally after 6", occasionally when smaller
-Extremely visible teeth
-Large head with straight profile​

Academic Diagnostic Traits

The GATF is the largest species of Hydrocynus. It has the least distinctive stripes of the genus. It has between 53 and 58 pored scales on the lateral line. The anal fin has 3 soft, unbranched rays and usually 12 branched rays. The dorsal profile of the head is straight. The depth of the body in adults is 19.4 to 32.7 percent of the length, with an average of 23 percent. The length of the head is 19.2 to 23.1 percent of the total length. The teeth can have between 12-20 in the upper jaw and 8-14 in the lower jaw. This wide variation is due to their having several small teeth that may or may not protrude through the gums near the back of the mouth. These fish are silvery in color with a red tail that most often only has color on the lower lobe. Coloration will often be washed out in extremely young individuals.​

Size

GATF are the largest species of African tiger fish. The average adult specimen will be be two to three feet long and approximately 25 pounds. The current world record is 99 pounds, three ounces and was caught in 1987 by Daniel Neuville. In an aquarium, it is exceptionally rare to see a specimen larger than two feet.​

The world record Hydrocynus goliath.
​

Introduction, Acknowledgements & Suggested Reading
General Care
Key to Species
Hydrocynus goliath
Hydrocynus brevis
Hydrocynus forskahlii
Hydrocynus vittatus
Hydrocynus cf. "stout vatf"
Hydrocynus cf. "big eye"
Hydrocynus tanzaniae
References

 

[Chicxulub]

Hydrocynus brevis

Hydrocynus brevis courtesy C Chicxulub ​

General Info

Brevis is a species of very large African tiger fish. They are fairly rare in the hobby, but not unheard of. They are probably the rarest ATF in the West. These fish are not intentionally imported and come in as contaminants with shipments of H. forskahlii. Brevis are a large, attractive species of ATF that is often severely underappreciated; most people who get them assume they have the sympatric and very closely related forskahlii. As they get large, brevis tend to become very goliath-like in form, they look like a gold colored goliath with a slightly smaller jaw. In fact, in their native range they often fill the same ecological niche as goliath. When they are small, these fish are extremely easy to confuse with forskahlii and are often sold as forskahlii. If you want to get one, you have to either find a very knowledgeable distributor or get lucky and spot one mixed with a shipment labeled as forskahlii.

Brevis has a reputation as being very aggressive and capable of damaging other fish, often more so than its congeners. This is due to an unusual feeding method as described by Lewis (1974) which states that brevis, uniquely among the African tiger fishes, routinely feeds on fishes larger than itself. The brevis will attack a larger prey item in the back third of the prey fish’s body in order to amputate the tail. Once the prey item is incapacitated and has floated to the surface, the brevis will eat the prey item at its leisure. Caution should be exercised when housing brevis with other fish. The author can testify to the fearless, bold nature of Hydrocynus brevis. He kept a young specimen that was singularly fearless; this species is easily the boldest and most aggressive species. The author's six inch BATF would terrorize his foot long GATF.

An incredibly bold 6" BATF hand feeding. Courtesy Chicxulub.​

Distribution

-Nile River
-Sanaga River
-Omo River
-Gambia River
-North flowing rivers in western Africa​

Diagnostic Traits for Hobbyists

-3-4 scales between the lateral line and pelvic fin insertion. FATF has two.
-Red or reddish orange on the lower lobe only.
-Golden or dusky color.
-Often extremely shiny.
-Very indistinct stripes that don't go over the back.
-Has a massive head when compared to forskahlii.
-Much thicker body in relation to forskahlii.
​

A comparison of a very young brevis with a very young forskahlii. Brevis on the bottom, forskahlii on the top.


BATF and FATF head details showing the difference between their heads. Brevis will have a much more massive, goliath like head. The preorbital bone will be much larger, giving the impression of a longer head. In this image, the FATF is above, the BATF is below. Courtesy Chicxulub.


Diagnostic of BATF and FATF by Woody Cotterill and Sarah Goodier. If anyone knows the name of the article that this was published in, please let me know so that I can cite them properly!​

Academic Diagnostic Traits

Except for Hydrocynus goliath, BATF has the least developed striping of all members of the genus. 3-4 scales between the lateral line and the pelvic fin insertion. BATF have a lateral line scale count of 47-55 pored scales. Anal fin ray count 3 soft, unbranched rays with 11-13 branched rays. BATF on average has the deepest body to length ratio with an average of 24.4 percent and a range of 19.1 to 29.6 percent of the total length. BATF have 10 to 12 teeth in the upper jaw and 8 to 13 in the lower jaw. BATF have a golden or dusky base color with tan or grey paired fins. The adipose fin is often very large in relation to the other ATF species. Their caudal fin has a base of dark gray with a very dark red lower lobe. Coloration will often be washed out in extremely young individuals. Coloration will often be washed out in extremely young individuals.​

Size

Adults are typically 18 to 24 inches in length, though some may grow quite a bit larger. There is very little data available on the size that these achieve in an aquarium, but there is reliable data of a few that topped 12 inches and one monster that was 26 inches when it died. As such, these fish should be considered to be the equals of VATF in their care needs. The current world record is 28 pounds, eight ounces and was caught by Marc Towers in 2012.​

The world record Hydrocynus brevis.​

Introduction, Acknowledgements & Suggested Reading
General Care
Key to Species
Hydrocynus goliath
Hydrocynus brevis
Hydrocynus forskahlii
Hydrocynus vittatus
Hydrocynus cf. "stout vatf"
Hydrocynus cf. "big eye"
Hydrocynus tanzaniae
References

 

[Chicxulub]

Hydrocynus forkskahlii

Forskahlii tigerfish, courtesy of A aceface562 ​

General Info

Hydrocynus forskahlii is very unique among the African tiger fishes in that it is probably the only one that is actually suitable to be kept in an aquarium, which is a very good thing as they are one of the most readily available species as well. They are truly a dwarf species, at least when compared to the monsters that the other four species can become. These fish can be kept for life in a tank that is as small as a 180, though they'd probably be happier with the extra room to swim in a 240. Forskahlii are also a very attractive and colorful species, generally having the same color patterns as a vittatus. These fish also tend to have fairly dramatic teeth for their size. There is a fair amount of variation in the morphology of forskahlii as there are two distinct genetic populations awaiting scientific description.​

Distribution

-Nile River
-Sanaga River
-Omo River
-Gambia River
-North flowing rivers in western Africa
​

Diagnostic Traits for Hobbyists

-Two scales between the lateral line and pelvic fin insertion.
-Greyish tail with red, orange or yellow color only on the lower lobe.
-Small, thin head compared to every other species.
-Large eyes in comparison to BATF.
-Thin, elongate body.
-Light gray to dark grey, squarish adipose fin.​

A comparison of a very young brevis with a very young forskahlii. Brevis on the bottom, forskahlii on the top.


BATF and FATF head details showing the difference between their heads. Brevis will have a much more massive, goliath like head. The preorbital bone will be much larger, giving the impression of a longer head. In this image, the FATF is above, the BATF is below. Courtesy Chicxulub.


Diagnostic of BATF and FATF by Woody Cotterill and Sarah Goodier. If anyone knows the name of the article that this was published in, please let me know so that I can cite them properly!​

Academic Diagnostic Traits

FATF have pronounced stripes. They have two scales between the lateral line and the pelvic fin insertion, as opposed to 3-4 for a brevis. They have a lateral line scale count of 46-53 scales. Their anal fin ray count is 3 soft, unbranched rays with 11-14 branched rays. Body depth averages 22.6 percent of the length with a range of 17.2 to 27.8 percent. FATF is normally the most slender member of Hydrocynus, but girthy specimens are possible. The head averages 19.8 percent of the body length with a range of 15.3 to 25.3 percent. FATF has 9 to 14 teeth in the upper jaw and 8 to 12 in the lower jaw. This fish often has a very short, upturned jaw. FATF are bright, silvery white in color, similar in appearance to VATF, but with a grayish caudal fin that has red, orange or yellow only on the bottom lobe of the caudal fin. Coloration will often be washed out in extremely young individuals. FATF will often overlap H. brevis in range.​

Size

Wild specimens are normally less than 12 inches. A large specimen will be 18 inches and five pounds. In an aquarium, it is very rare for one of these fish to top ten inches. The world record fish is nine pounds, zero ounces and was caught by Jeff Currier. The date of capture isn't reported.​

The world record Hydrocynus forskahlii

Introduction, Acknowledgements & Suggested Reading
General Care
Key to Species
Hydrocynus goliath
Hydrocynus brevis
Hydrocynus forskahlii
Hydrocynus vittatus
Hydrocynus cf. "stout vatf"
Hydrocynus cf. "big eye"
Hydrocynus tanzaniae
References
​

 

[Chicxulub]

Hydrocynus vittatus

Vittatus tigerfish courtesy of ShadowStryder ​

General Info

Vittatus is easily the most commonly available species in the hobby. This fish have the largest range in Africa and as such the largest genetic diversity; there are no less than five distinct genetic populations of vittatus. As you might expect, there is a considerable amount of variability in the way these look. Fortunately though, all of the members of the clade known as the Vittatus Complex share diagnostic traits which distinguishes them from the other four species. Vittatus are colorful, personable fish that can incredibly rewarding to keep if you have the means to house them.​

Distribution

-Congo River and tributaries
-Zambezi River
-Okavango Rivers
-Coastal river systems south of the Lower Zambezi
-Lake Tanganyika
-Zambian Congo​

Diagnostic Traits for Hobbyists

-Black at the tip of the adipose fin. Often clear or greyish in younger fish.
-Stripes generally evenly saturated and bold.
-2 scales between the lateral line and pelvic fin insertion.
-Rounder, more blunted head than cf. "big eye".​

​

Academic Diagnostic Traits

VATF have pronounced stripes. They have two scales between the lateral line and pelvic fin insertion. They have a lateral line scale count of 45-50 pored scales. They have an anal fin ray count of 3 soft, unbranched rays and 11 to 12 branched rays. Body depth ratios were not elaborated upon in the scientific literature, but it was noted that “H. vittatus seems generally more massive than H. forskahlii." Exact numbers of teeth are not elaborated upon in the description by Paugy and Guegan (1989). VATF are a bright, whitish silvery color. They can have red, orange or yellow caudal fins with both lobes having color. The center of the caudal fin, regardless of color, is often red. Paired fins are often pale yellow or orange. The anus is often orange or red. Coloration will often be washed out in extremely young individuals. It is interesting to note that VATF from the Upper Zambezi display sexually dimorphic coloration. Mature males had bright yellow caudal fins with bright red markings on the bottom lobe. Mature females had bright orange caudal fins.​

Size

Adult vittatus are normally eighteen to 24 inches in length. In an aquarium, the normal size for these fish seems to be twelve to eighteen inches. Anything over 18 inches should be considered exceptional. The world record vittatus was 35 pounds, eight ounces and was caught in 2001 by Jennifer Daynes.​

The world record Hydrocynus vittatus.
​

Introduction, Acknowledgements & Suggested Reading
General Care
Key to Species
Hydrocynus goliath
Hydrocynus brevis
Hydrocynus forskahlii
Hydrocynus vittatus
Hydrocynus cf. "stout vatf"
Hydrocynus cf. "big eye"
Hydrocynus tanzaniae
References
​

 

[Chicxulub]

Hydrocynus cf. "stout vatf"

Hydrocynus cf. "stout vatf" courtesy sunnysjourney ​

General Info

Hydrocynus cf. "stout vatf" turns up in the hobby from time to time, but is often overlooked. This variety possibly corresponds to one of the members of the Hydrocynus vittatus species complex: genetic lineages B, C or D from Goodier, S., Cotterill, F., O'Ryan, C., Skelton, P., de Wit, M. (2011). These fish more or less look exactly like a Hydrocynus vittatus sensu stricto, but have more scales between the lateral line and pelvic fin insertion than do VATF, and they typically have fewer lateral line scales on average than do vittatus. Other than the generally thicker body shape and scale counts, these fish are nearly indistinguishable from Hydrocynus vittatus s.s. These typically come in with shipments containing true VATF that are not mixed with goliath.
​

Distribution

-Somewhere in the Congo drainage, exact location unclear.​

Diagnostic Traits for Hobbyists

-Broadly similar to VATF.
-A much thicker body than VATF when larger.
-Scale counts off; VATF with 3-4 scales between LL and pelvic fin insertion.​

​

Academic Diagnostic Traits

Not formally described. Broadly matches the overall appearance and published description of Hydrocynus vittatus s.s., but with 3-4 scales between the lateral line and the pelvic fin insertion and often fewer lateral line scales than H. vittatus s.s. Possibly corresponds to genetic lineage B, C or D from Goodier, S., Cotterill, F., O'Ryan, C., Skelton, P., de Wit, M. (2011). Known from the Congo watershed, exact location unclear. VATF are a bright, whitish silvery color. They can have red, orange or yellow caudal fins with both lobes having color. The center of the caudal fin, regardless of color, is often red. Paired fins are often pale yellow or orange. The anus is often orange or red. Coloration will often be washed out in extremely young individuals. VATF from the Upper Zambezi display sexually dimorphic coloration; it is unclear if this applies to cf. "stout vatf". Mature males had bright yellow caudal fins with bright red markings on the bottom lobe. Mature females had bright orange caudal fins.​

Size

Specimens have been known to reach 15" in aquaria.​

Introduction, Acknowledgements & Suggested Reading
General Care
Key to Species
Hydrocynus goliath
Hydrocynus brevis
Hydrocynus forskahlii
Hydrocynus vittatus
Hydrocynus cf. "stout vatf"
Hydrocynus cf. "big eye"
Hydrocynus tanzaniae
References

​

 

[Chicxulub]

Hydrocynus cf. "big eye"

Hydrocynus cf. "big eye" courtesy M MonsterFang ​

General Info

Hydrocynus cf. "big eye" is a relatively common ATF in the hobby. Until recently, these were thought to represent Hydrocynus tanzaniae because the scale counts match that species perfectly. The author harbored doubts about this however, due to the frequent association of this species with Hydrocynus goliath; the association of these two species was far to frequent to be a coincidence. Upon further investigation, I was able to uncover reliable data that these fish are from the lower Congo and live along side of Hydrocynus goliath, making it impossible for these fish to represent Hydrocynus tanzaniae. As such, these fish are also an undescribed population, likely representing either a genetic lineage from the Vittatus Complex comprising lineages B, C and D or the undescribed species represented by lineage A from Goodier, S., Cotterill, F., O'Ryan, C., Skelton, P., de Wit, M. (2011). These fish are unique among ATF in that they seem to favor the bottom of the water column. They typically are associated with shipments of true VATF that are mixed with goliath.

​

Distribution

-Lower Congo, sympatric with Hydrocynus goliath and Hydrocynus vittatus s.s.​

Diagnostic Traits for Hobbyists

-Broadly similar to VATF.
-A much thicker body than VATF when larger,
-But overall far more streamlined and torpedo shaped.
-Scale counts off; perfectly matches TATF.​

Academic Diagnostic Traits

Not formally described. Broadly matches the overall appearance and published description of Hydrocynus vittatus s.s., but scale counts perfectly match those of Hydrocynus tanzaniae: 43-47 lateral line scales and 3 scale rows between the lateral line and the pelvic fin insertion. Known from the lower congo, sympatric with Hydrocynus goliath and Hydrocynus vittatus s.s.. Cf. "big eyes" are a bright, whitish silvery color. They can have red, orange or yellow caudal fins with both lobes having color. The center of the caudal fin, regardless of color, is often red. Paired fins are often pale yellow or orange. The anus is often orange or red. Coloration will often be washed out in extremely young individuals. VATF from the Upper Zambezi display sexually dimorphic coloration; it is unclear if this applies to cf. "big eye". Mature males had bright yellow caudal fins with bright red markings on the bottom lobe. Mature females had bright orange caudal fins.​

Size

Specimens have been known to reach 12" in aquaria; they likely get somewhat larger.
​

Introduction, Acknowledgements & Suggested Reading
General Care
Key to Species
Hydrocynus goliath
Hydrocynus brevis
Hydrocynus forskahlii
Hydrocynus vittatus
Hydrocynus cf. "stout vatf"
Hydrocynus cf. "big eye"
Hydrocynus tanzaniae
References

​

 

[Stormowl]

*commandeered for Guide usage*
Hydrocynus tanzaniae

Hydrocynus tanzaniae. I've had this pic forever, but I don't remember where it came from. This is the only in-tank shot I've ever seen that appears to match a true tanzy.​

General Info

Completely absent from the hobby. What we thought were TATF were in fact cf. "big eye", which matches the scale counts for Hydrocynus tanzaniae perfectly, but is indisputably from the Congo river.
​

Distribution

-Rufiji River
-Ruasha River
-Eastward flowing rivers in Tanzania north of the Zambezi​

Diagnostic Traits for Hobbyists

Completely absent from the hobby.​

Academic Diagnostic Traits

TATF have pronounced stripes. There will be 3-4 scales between the lateral line and the pelvic fin insertion. They have 43-47 lateral line scales. They are distinct from the rest of the species in the genus by having elongated third and fourth dorsal and anal fin rays, though if this should be damaged it may not grow back. The anal fin has 3 soft, unbranched anal fin rays and 12 or 13 soft, branched anal fin rays. The body has a mean depth ratio of 23.8 percent of the standard length, with a range of 20.0 to 26.6 percent. The length of the head is 18.3 to 22.2 percent of the body length. TATF have 13-16 teeth in the upper jaw and 10 to 12 in the lower jaw. TATF have a silvery-gray body with dark stripes. The second stripe above the lateral line is less pronounced than the other stripes. Their caudal fin can be blue or green or red or yellow. They often have various markings of blue, green, grey, pink, yellow or red. TATF occasionally have a steel blue adipose fin, although this may not be obvious when young or without bright lighting. Coloration will often be washed out in extremely young individuals.​

Size

Closely resembles vittatus; adults are normally 18 to 24 inches in length. Large adults over two feet long seem to be much more common than with vittatus, even though the world record for tanzaniae is smaller. Due to the lack of specimens in captivity, it is hard to say conclusively how large they would get, but due to the close relation with vittatus, it is likely that only exceptional specimens would exceed 18 inches. The world record is 26 pounds, zero ounces and was caught in 2010 by Michael Tarr.​

The world record Hydrocynus tanzaniae.​

Introduction, Acknowledgements & Suggested Reading
General Care
Key to Species
Hydrocynus goliath
Hydrocynus brevis
Hydrocynus forskahlii
Hydrocynus vittatus
Hydrocynus cf. "stout vatf"
Hydrocynus cf. "big eye"
Hydrocynus tanzaniae
References

Original post:

I don't keep ATFs, and don't have the means to do so. But with that said, this was a wonderfully well-written and informative article. I enjoyed reading it, and am really impressed with how well done this is!