Decreased aggression in captive bred fish.

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Cherrybomb

Feeder Fish
MFK Member
Jun 12, 2022
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Hi everyone, I have a question that's weighing on my mind. I've talked to different people and have heard that cb fish are getting less aggressive than they were years ago. Oscars and Jack's in particular I keep hearing aren't like they were in the 80's. Even the gold and silver saums and some managuenses have grown softer. Do you think that dovii, umbi and some of the others will follow suit?
 
I can't answer for anyone else but my fish haven't gotten the message. My Oscar (cb presumably) has peeled two synos (one kill with a broken tail section), bitten the head of a severum and stressed it to death. He is inseparable from his parrot, Boss. Two days ago one of my hrp attacked the eyes of my current severum (territory). I think the wild thing is overblown. Some people say wilds are more aggressive, others say more skittish.
 
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I don’t think you can breed aggression out of these fish. In fact, they might be more aggressive because they are often kept in smaller glass boxes forcing them to compete more for space, food and mates. An aquarium is usually the reason for aggression in the first place. Can’t blame the fish, they are just stuck in a much smaller space and doing how they know to survive.
 
It depends on your definition of aggression.
I bought my first Ossar in 1958. And it ate guppies, and any fish that fit in its mouth.
Bet any oscar would also do so today
When an oscar eats a guppy, is that aggression?
Do you considered a human eating a hamburger aggression?
When we are eating that burger, we are in fact, contributing to the killing, of a very large sentient animal, at that moment do you feel malice toward it? feel aggression?
But maybe more to the point, I have seen dovii act downright placid in 500 gal + tanks, but...
put them in a 100 gal tank and they kill everything else.
Is that aggression, or just instinctual survival in the amount of space it is crammed into.
Even back in 58, I never considered oscars aggressive, and still don't.
In fact compared to the instinctual territoriality of many other cichlids, oscars are pussy cats
 
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Hi everyone, I have a question that's weighing on my mind. I've talked to different people and have heard that cb fish are getting less aggressive than they were years ago. Oscars and Jack's in particular I keep hearing aren't like they were in the 80's. Even the gold and silver saums and some managuenses have grown softer. Do you think that dovii, umbi and some of the others will follow suit?
I personally hear and experience the opposite. Captive bred fish are strangely more murderous than their wild counterparts.
 
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Thanks everyone, what I was referring to was cb vs cb in the same size aquariums. Not exactly predation but just aggression towards tankmates in some of the same size tank. Say for instance, you bought a certain species, different individuals, about 30 years ago. Your favorite kind of fish, that you keep buying but over the years they're not as aggressive in your aquarium, with the same kinds of tankmates. I know that each has it's own personality. Just what I keep hearing about the "good old days". One example is an old tfh article about datnoids that said that they were so aggressive that only puffers can be with them but the puffers would eventually kill them. I had a good green one take a bite out of a jewel that kept picking at it, now jewels aren't even considered aggressive for the most part. To me eating something is not really aggression, just killing something is. I lost a tsn, birthday gift, to a jaguar female from predation. Same thing happened when I had piranhas. I consider those predation and not aggression.
 
Thanks everyone, what I was referring to was cb vs cb in the same size aquariums. Not exactly predation but just aggression towards tankmates in some of the same size tank. Say for instance, you bought a certain species, different individuals, about 30 years ago. Your favorite kind of fish, that you keep buying but over the years they're not as aggressive in your aquarium, with the same kinds of tankmates. I know that each has it's own personality. Just what I keep hearing about the "good old days". One example is an old tfh article about datnoids that said that they were so aggressive that only puffers can be with them but the puffers would eventually kill them. I had a good green one take a bite out of a jewel that kept picking at it, now jewels aren't even considered aggressive for the most part. To me eating something is not really aggression, just killing something is. I lost a tsn, birthday gift, to a jaguar female from predation. Same thing happened when I had piranhas. I consider those predation and not aggression.

What size aquariums are we talking about? 55g 4ft aquarium 40 years ago versus 8-10 feet long aquariums? if you think about it, there wasn't a wealth of information on proper care before 2003. Information was sparse on the internet, and not appropriate stocking was done. Lots of people stocked to the 1" per gallon rune. Over the years, people learned, and some began stocking less or stocking appropriately for potential adult size.
 
I don’t think you can breed aggression out of these fish. In fact, they might be more aggressive because they are often kept in smaller glass boxes forcing them to compete more for space, food and mates. An aquarium is usually the reason for aggression in the first place. Can’t blame the fish, they are just stuck in a much smaller space and doing how they know to survive.
Dunno, has anyone seriously tried breeding their lines based on peaceful behavior more than looks and/or ability to survive a survival of the fittest situation?
If we can do it with other animals. . .
 
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Dunno, has anyone seriously tried breeding their lines based on peaceful behavior more than looks and/or ability to survive a survival of the fittest situation?
If we can do it with other animals. . .

Not really.... getting faster or more profit has always been the factor for breeding fish. They are not considered working animals so there is no desire to spend additional money and time towards making more "domesticated" fish. With other animals, breeding traits so that the animals work better with people has been driving factor in domestication.
 
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