Keep 3 oscars in your 125 (is it a 4x2x2?) if you get a pair take the 3rd oscar out its as simple as that they may all be fine, you never know until you try it yourself you know if they don't get along or looks too small for your oscars.
no way a full grown oscar could live life in a 29 gallon tank and be healthy. i kept my 14" oscar in a 55, granted he was a bit cramped i moved him into a 125 (72x18 footprint) and had 2 8" oscars with him with more then enough room for more fish. but that strayed afar from my point. there is no way an adult oscar could live life in a 29 gallon tank.
Depends on how you're defining "worked." If by "work," you mean it will survive for a year or two before dying of ammonia poisoning and multiple possible deformities, then sure, it will "work" fine. However, if by "work," you mean the fish will be healthy and live to its full potential, then no; it would take a magician to make that "work."I have neil proneks book on oscars and he says if you have a 29 gallon tank it would be perfect for a single adult oscar and a 55 gallon would be perfect for a pair. It shows that a 125 is easily enough for 3 oscars some people will say things have changed since that book was written (1972) if i worked then it would now especially with better filtration.
Depends on how you're defining "worked." If by "work," you mean it will survive for a year or two before dying of ammonia poisoning and multiple possible deformities, then sure, it will "work" fine. However, if by "work," you mean the fish will be healthy and live to its full potential, then no; it would take a magician to make that "work."