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

thebiggerthebetter

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A week later: out of the remaining 3 smaller dorado, one schools with the bigger ones, it is the biggest, the other two cower in the tank corners most time, no good, all 3 fight a LOT, much more than the original batch. The two in the corners stopped feeding, so I took the real beat up one to a different tank. The other remained just as miserable in its corner, so I soon transferred it to the same tank. Only the 3rd one remains in with the bigger 8 dorado:

 

thebiggerthebetter

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The last smaller dorado that had been schooling with the bigger 8 got attacked and must be moved:

 
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jjohnwm

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Dorado have always been on my bucket list of fish to catch by angling; not so much as an aquarium fish. Sadly, your experience with them only reinforces that idea. Too bad, because a school of those motoring around in your big tank (25000gallons?) would be an incredible spectacle, but...a little too much drama, a little too high-maintenance...sounds like trying to control a roomful of 14-year-old girls.

If I ever tried keeping fish that turned into a bunch of homicidal lunatics every time I was late with a meal...I would have gotten out of the hobby decades ago! :)
 
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thebiggerthebetter

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Well, this following fight is not about feed. But maybe they will give me a bit of room to breath, seems to have been more stable after this last move (overall, the situation is still intense, and constant vigilance is a must):

 
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kendragon

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Definitely not for the weak hearted. I know they are an aggressive fish but this is off the chart.
 
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thebiggerthebetter

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The situation has become stable

- 8 bigger dorado together,
- the 1st and 2nd smaller together,
- the 3rd smaller apart from all other dorado.

Who knows for how long.

 

thebiggerthebetter

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Some great input from YT from a peer to who the dorado are local.

on the video: 1 week: 2 smaller dorado must go, 1 stays, all 3 fight bad; bigger 8 don't fight...

@FernandoReynoso Greetings from Uruguay, mostly the attacks are given by dominance since it is a new territory and the shoal is small, a dominance will be formed first and they will attack the young males, and if possible kill them, the females are calmer but the males are the that generate those attacks, greetings from the land of dorado...
TBTB: Thank you Fernando! Appreciate to know this and it does seem logical. Is there a growth rate and adult size disparity between the genders in these fish?

FR: I thank you for your comment, and if there is a disparity in size, females can double their size and weight in half the time of males, they generate greater body fat growth and their growth increases a lot, in my cases live food It is essential and at this stage, the ones you have still feed a lot on insects, such as crickets, cockroaches, grasshoppers and some beetle caterpillars. .... They are also usually fish that form a territory, Salminus brasiliensis, and fransicanus, they are fish that usually live in groups, mostly when it is the breeding season, here in Uruguay it is from October to March... and after that they are fish that can live alone without the shoal, so if you keep a specimen alone for some time and it takes that aquarium as its territory, it will attack and kill any other specimen that enters, especially if the specimen is male, that aggressiveness increases..
TBTB: much appreciate your sharing firsthand knowledge, glad to learn from someone to who these magnificent creatures are local.

FR: I love your work friend and I am fascinated by all the fish you have and the large aquariums, it is more than a pleasure for me to share part of my knowledge with one of the most loved species in my country since it is a highly sought after sport fishing fish Here, I live 3 hours from the dam where it is very common to catch specimens weighing more than 20 kilos and 1.20 m long, they are the females of the species, it is a magnificent predatory fish and for me the owner of my dreams in the carnivorous monster fish that I always wanted to have. I hope you enjoy those fish a lot, my friend, you have the King of the Uruguay River in your hands and in a good school, from the characteristics and color of their tails I can say that it is Salminus franciscanus, very common in the rivers of Bolivia, and highly appreciated for its fly fishing..
TBTB: much appreciated, thank you greatly! I wasn't sure if our dorado were franciscanus or brasiliensis. I thought the dorado from rio Parana and its tributaries like rio Uruguay must be brasiliensis, no?

SPECIES IDENTIFICATION:​

FR: If your dorados were sent from Argentina or Paraguay or Uruguay, it is very likely that they are Salminus brasiliensis, if it is more on the rivers, higher up like Bolivia, and Peru and part of the Brazilian Amazon, it is already more the Franciscanus, although the coloration is more silver of your specimens, it may also be the S, affinis or bilarii that are specimens from further north in South America. We would have to wait for the growth and see how the coloration ends up defined, for me they are more Franciscanus, but I could be wrong x that they are still juveniles and end up in another variety when they are more adults and mark their total maturity..
TBTB: I can't thank you enough for this input! Thank you and I am / we are lucky you decided to share your firsthand knowledge!

FR: It is a pleasure for me to share the knowledge I have about these fish, which is still not enough because I still have a lot to learn about them, but I always love sharing what I have learned from them with people who share my same hobby and more when it comes to Dorados.. any questions you have and want to know about them and the answer is within my reach, I will gladly inform you, friend..


**********************

on the video: 11 minutes of 2nd & 3rd smaller dorado fighting, looks like to death...

FR: This is a fight for dominance, they seek to control the territory and they will fight, until one dominates the others or I end up killing them, it is very common in the males of the species.
TBTB: thank you for this. I wonder why in the group of the 8 bigger ones this is not happening. Also why the 1st smaller one was fighting with the 2nd smaller one badly in the tank with the 8 bigger ones, and the 1st and 2nd fought badly with the 3rd smaller one that schooled with the 8, but the 1st and 2nd stopped fighting with each other after I separated them both into a different tank where they are still together but no other dorado.

FR: As you could see in the video where they were both in the same aquarium as the rest, there were only the two of them together and fighting was due to the fact that the rest of the specimens are larger and they were taken as inferiors, so the only way not to dying was, not fighting with the elders and between them there was a fight for which of the two Hera dominated, (in the world of dorado, dominance is key, for their future as a reproducer, and since they are born, dorados are at being born are cannibals, and from there their control over dominating the other is always stronger and more so when there are females, this increases when the females are fertile at 3 or 4 years and about 4 to 5 kilos in weight and about 40 cm, in the males, the fight is from youth since they are the ones who will carry a strong gene to the future generation ..
TBTB: Thank you. Useful good info, much appreciated! I apologize, but to me the two questions remain unanswered - why the 8 bigger dorado stopped fighting (for now?) and why the 1st and 2nd smaller dorado stopped fighting when alone in their tank. Maybe you answered it but the translation is not letting me understand the answer, or maybe I am too dense. Sorry.

FR: Sorry, I don't think I answered your questions, the big dorados have stopped fighting because the dominance of that group is led by the females, so after taking control of the school, the conflict ends, and the males go to being part of the domain of alpha females, which in the species is very common x being the largest and strongest... and in 2nd point, to the 2 due specimens, the one with the most damaged caudal fin, that is, the smallest He also has a wound, he was the one that ended up dominated, so the older male will no longer attack him so much, only on occasions so that he continues to know who is in charge, nothing else... that will continue with the passage of time and growth, the dominance The territorial dorado never ends and there will always be and you will see some small forms of attack and circles that will mark the dominance and control of the weakest specimen... I hope this is the answer you are looking for and if not, I will gladly find a way for you to understand them better friend ..
TBTB: This is great, thank you, I think I understood. The 8-pack is now led by females. I didn't expect this answer, this is great! That the two smaller dorado stopped fighting in the isolation could be simply coincidental, that is they might have stopped fighting even if they were left in the tank with the 8 bigger + 1 smaller. Although I think them fighting so much before was influenced by the 8+1 dorado, and might have not stopped.
 
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thebiggerthebetter

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Now that all the dorado are bigger by several inches - the 3 from the 2nd batch are ~6"-7", still about 1-2 inches behind the biggest from the 1st batch of 8 but equal to the smallest from the first batch - we are trying to make them live together for a second time:

 

thebiggerthebetter

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The 11 have been doing well, much more stable. Overall growth rate is from 2" to 7"-8" in 2-3 months. They are now about 5 months old.

 
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