I had a 50 gallon community tank, with a school of silver tip tetras, some cardinals, some bleeding hearts, a couple of fancy corys, a small bristlenose and a huge pair of retired/culled marble double veiltail angels. I also had one red and one lavendar cambodian betta male in the tank. They would flare if they saw each other, but basically had territories on opposite ends of the tank. I never saw them fight. It was a planted tank with plenty of structure, wood, some piled up rock, etc. The red betta hung out in a big clump of cabomba and the cambodian stayed in some corkscrew vals that were long enough to lay along the surface of the water.
I also had a 55 that had 5 oscars, a 19" clown knife, a 20" black ghost, an Armatus spiny eel about 25" long and several catfish, a TSN, several huge striped doradid cats and a snow king pleco. I was able to keep all that rough stuff in there because I did 4 times a week 70% water changes. I generally fed feeder goldfish, feeder livebearers and some tetra tabimin and spirulina wafers for the catfish. They basically just kept growing after being introduced as babies. The eel went in there at 5" long, for instance. I worked for a fish wholesaler in West Haven, Ct. I did eventually move 4 of the oscars to 2 other 50's. They paired.The other oscar stayed in with the bruisers.
I actually spawned both pairs of oscars many times. They basically paid the rent on the apartment. I also seperated the angelfish pair because they were trying to spawn in the community tank. I gave them their own 30 gallon tank and fed them mainly live brine shrimp and some occasional daphnia, if the boss got some in. I'd get a couple of hundred angels at least once a month. I'd get upwards of a 1000 oscars at least once a month. I'd sell the oscars at about 1 and 1/2 " to the wholesaler I worked for. The angels went at around the same length.
I wound up working nights as a cook in a big restaurant, and worked mornings at the fish wholesalers. I did tank maintenance all afternoon once the fish started spawning, so it all worked out.
