My first dip with dorado, sold as brassie by Rapps, thought to be frankie

[jjohnwm]

Viktor, is there any chance to do the scale count on a dead one of those little dorado? If you have access to a low-power dissecting microscope, or perhaps a high-quality, higher-magnification illuminated lens mounted on a cantilevered arm, perhaps this would be possible? I realize that those scales are pretty tiny, but good optics can reveal some astonishing detail. Or perhaps a quality macro lens used to take a well-lit series of photos of a living specimen held briefly in a net?

In the world of birding, there is constant and ongoing debate regarding the actual identity of individual birds that are still free-flying in the wild, based entirely upon observation and also analysis of photographs. To those folks, a "bird-in-the-hand", so to speak, would be a godsend.

 

[DB junkie]

I believe the issue with a lateral line scale count is that Brassies and Frankies have an overlap in number of scales per species. Depending on the number it could be inconclusive.

Nevermind - the overlap is VERY minimal. Chances the number you come up with IS going to give you a positive ID...... Assuming the savages leave you enough left of the corpse for a count.

 

[thebiggerthebetter]

Thank you guys. I will ponder about the scale counting.

Short term success here - upped the feeding 3x, no attacks in a week.

 

[thebiggerthebetter]

Salminus franciscanus summary page

www.fishbase.se

This species is distinguished from all its congeners, except S. brasiliensis, by the following characters: presence of a second dentary tooth in the outer tooth series that is considerably larger than the remaining teeth (vs. second dentary teeth only slightly larger than remaining teeth in S. affinis and S. hilarii); it differs from S. affinis by the absence of the dark post-orbital stripe (vs. present); differs from S. brasiliensis in having 68-82 (modally 77) lateral line scales (vs. 79-102, modally 96), 11-14 (modally 12) horizontal scales between dorsal-fin origin and lateral line (vs. 14-18, modally 16), and 6-8(modally 6) horizontal scales between lateral line and pelvic-fin insertion (vs. 6-9, modally 8). In spite of the great overlap, compared to the sympatric S. hilarii, this species has generally more scales on the lateral line (vs. 54-72, modally 65-66), horizontal between dorsal-fin origin and lateral line (vs. 9-12, modally 10), and horizontal between lateral line and pelvic-fin insertion (vs. 4-7, modally 5); it also differs by having a golden coloration mainly over the facial bones and pectoral girdle (vs. facial bones and pectoral girdle silvery).


There is little published information about the general biology and ecology of this species when compared to its much better known S. brasiliensis, even though this species has been recognized as distinct (even if under misapplied names) since late 19th century. Under the name S. brasiliensis, it has been reported to reach one meter in total length and weigh up to 30 kg, consequently, one of the largest known Characiformes; piscivorous; undertakes reproductive migrations during the rainy season; juveniles (< 600 g) were collected in marginal lagoons of the rio São Francisco, an indication that these are recruiting habitats for the species; one of the main targets of the commercial and amateur fisheries in the middle rio São Francisco basin.

Max length : 75.5 cm SL male/unsexed

Brasiliensis

Salminus brasiliensis summary page

www.fishbase.se

South America: Paraná, Paraguay, and Uruguay River basins; Laguna dos Patos drainage, upper Chaparé and Mamoré River basin in Bolivia. Occurrence in the remaining Amazon River highly doubtful.

Maturity: Lm 37.9 cm
Max length : 100.0 cm SL male/unsexed;
max. published weight: 31.4 kg;
max. reported age: 9 years

 

[DB junkie]

Panara Basin. I know that's where the wolves came from that were imported along with the first Brassie I had.

Was told they were a quota'd species down there, hence the reason they were rare and expensive......

 

[kendragon]

I've never seen a Brassie pick on anything. I had issues with Frankies and Hillari picking eachother off. Sometimes it was the alpha, sometimees it was the smallest. I actually gave up on my Hillari once I got down to 4 from like 7. I just tossed them in with the Brassies assuming any result would be better then the one I was getting with just them in a tank. They all paced together and the aggression amonst the Hillari ended immidietly.

How big of a tank are they in???? IF you witness aggression in the group you should shrink the tank - see IF you get the same results I did. They only fought IF they had room.

I concur with DB's observation about tank size. I had my dorados in a 225g which they grew to a monster size and had no problems. These guys are highly aggressive even to their own kind.
One thing I did was to only feed pellets and I would give them as much as they can eat each time. Pellet will help a little with water quality vs fresh. You might remember that Jib and I kept dorados at the same time in similar tank size. I believe he fed fresh. Well, you can do the comparison and draw your own conclusion.
I don't believe the scale count is an accurate determinator of sp. which I kinda eluded to in my dorado growout thread. This is just me.

 

[Redshark1]

In all the videos I watched I seem to remember the adult Golden Dorado swimming singly among Piraputanga shoals on which they apparently feed.

 

[thebiggerthebetter]

The adults are indeed solitary, only joining together for migrations which are about 400km or 250mi, or so I read. So, yes, it is unnatural for adults to be near each other, so no big wonder they attack each other. Yet, peers report that brasiliensis don't do it, or don't do it much, vs franciscanus. Yet others say they see no difference, but the species ID may be muddling it up, causes doubt. Almost no one counts scales, and Ken above even says he doesn't believe the scale count is fruitful for the farmed fish, I suppose because in captivity the farmers may mix and match 2, 3 or 4 of the known dorado species, who knows.

The scale count should hold up for the wild specimen, I assume, but we probably get these next to never these days, given the availability and cheapness of the farmed dorado, same as with all farmed fish. In fact the temptation is to pass a farmed fish for a wild one to charge more and/or gain edge on competing vendors - I've always been wary of that.

 

[thebiggerthebetter]

Self-explanatory:

 

[Redshark1]

For me your videos and explanations are absolutely the best. Those Dorado are getting scary already. I'm glad you are experimenting with them it is definitely another of the world's most amazing fish that you need experience with.

I work with plants and when two species are crossed to produce a hybrid the progeny most frequently grow bigger and faster than the parents. This has been very important in forestry especially. We call this hybrid vigour. I expect it could be true with farming animals including fish too.