CichlidFish.com - Fish That Think.

I have 3 baby Oscars and a jack Dempsey in a 125gal tank. Will 3 Oscars be ok, or should I have 4.

I have 4 O's in a 150 gallon tank and it's tough. I thought it was huge (there are pics in the picture gallery). Three of them stay on the left side of the tank, and 1 on the right side. They defend their sides if one wanders to the other side of the tank. 3 are full grown and one is like 6 inches. After like half a year, I already need to upgrade to like 250+ gallons for them to all get along and have their own space. I would think all the fish you have in there now is enough, if not too much.

ONLY ONE of the larger Americans  species can live peacefully and you can have other tank mates .. YOU run the chance of a pair if you have more than ONE and if they are the same sex, then that makes it bad as the might get along and might not..

Three now, is a problem. YOU wil have a pair.. So the odd one out is going to catch the fire when the others two pair up..

So NO you don't want another one.. The JD is fine as he wil stay in a cave IF YOU have one for him.. And you wil have to move one of the Oscars later if two do pair up, so be aware of that later on..

NO you can not sex Oscars at this age.. YOU have to wait until they are a good 6" and then you need to VENT them from under neath.. Aggression might be a earily warning sign of a male if he chases ONLY one of them away from the others one.. THAT one will be a female.. You have 4 months OR so before this happens so you have time to figure it out.. 

YES Oscars are SO cute and SO small when you get them but they do get big FAST12+",  and MALES AND FEMALES wil get together and spawn.. All others in the tank are domed if not killed out right depending on the size of the tank.. some just stay on one side as Amy's one Oscar is doing.. Two many of the same species is a bad deal no matter how big the tank is.. They are confined and can not escape the others when they pair up and spawn..