Satanoperca's

[jeep04]

Not sure if this is better ask in a Cichlid forum but since i dont belong to any, i figured someone here might have experience with these fish. I have two Satanoperca leucosticta, 1x Geophagus colombian and 1x Geophagus pindare. The Pindare seems to be causing most of the aggression issues and he was the last one added. They are all close in size (within an inch) except the one luecosticta just doesn't seem to be growing, this is also the one that seems to be picked on the most. She is eating i make sure she gets extra and still she stays small,i don't think she has grown at all in the 5 months with me. They eat New Life spectrum 1 and 2 mm pellets and bloodworms as a treat once a week. There are plenty of hiding spaces (2 big driftwood pieces,1 hollow half log) and i even went as far as changing the tank around once a week for a month. I just keep reading that these fish are not aggressive which is not really the case even the colombian picks on my one loach. Just wondering if anyone else has had aggression problems with these fish and if a fish is acting completly fine but not growing , why that would be. Thank you

[Matt]

I'd say lack of numbers is causing the aggression - Satanoperca and most of the 'true' Geophagus are gregarious fishes which form social hierarchies. In a small captive group it's not uncommon for one specimen to become hyper-dominant as in your case. Changing the décor around won't help since these fishes aren't territorial unless breeding.

[Martin Thoene]

Yes, with a lot of social fishes there's a "critical mass" kind of thing where they only exhibit "true" behaviour once you reach or exceed that number.
Most of these Geophagines aren't exactly highly aggressive when not breeding, but as Matt says single specimens within a mixed species group can become hyper-dominant and cause major issues.
You don't state your tank size and this may have a bearing on how many it is possible to increase numbers by taking into consideration potential growth size in the future.

Martin.

[jeep04]

Well thank you for the response, i wish i would have got more but when i purshased all of these they were the only ones in the lfs tank. The satanoperca's were first and it was going to be only them but i ran into these other two by themselves, so i figured they would be ok or at least better then the 10g alone in the lfs. Right now they are in a 75g they will be going into a 100g which is only another foot long, so i'm not sure if i can hold more. Sounds like you guys know a decent amount about these fish, should i get rid of the pindare and Dicrozoster which would leave 2 leucosticta's. I don't think getting one more of those two would help and finding the same size would be almost impossible. Also i can't find anything around Pittsburgh other then jurapari which is close to leucosticta, any help would be great.

[Matt]

A mixed group of Satanoperca will work ok provided you don't allow them to interbreed - I kept S. leucosticta in with S. daemon for a few years without problems.

It sounds as though the small fish is a runt. This happens sometimes and there's little you can do about it. No doubt it's the target of excessive aggression because it's the weakest. This will be less of an issue in a bigger group but it might never grow very large.

The New Life pellets you're using as a staple diet only contain a low percentage of plant matter so I'd recommend introducing some into the diet. Are there any good quality algae or veggie-based foods with a small grain size available in your area? Also a large proportion of the natural diet of these fishes is chironomid larvae (bloodworm) so a couple of additional feeds of that per week wouldn't go amiss.

[jeep04]

Thank you Matt, i will get them some veggie matter in thier diet. I was told people feed this to tropheus which they are almost all veggie diet(or at least people think) so i'm surprised it isn't enough for them. Well i hope the Geo's and satanoperca's will be ok together because i really dont want to give any up, i went thru alot of fish before i found these guys and they are by far the most intresting fish i have kept.