An Oscar alone could reach a foot. The other fish 10-12". Three of them in a 75 gallon tank would be a nightmare to maintain!
Oscars alone produce an enormous amount of biological waste. Not to mention they are a South American cichlid that thrives in a softer water. Central American thrive in harder water. I can guarantee that if you mixed them together the Oscar would pit out somewhere down the road.
Look at a seventy five gallon tank as being an excellent grow out tank, or for a single pet fish, or maybe a tank for a isngle pair of breeders. If you are going to use it for a smaller species like Neets, Nicks or any one of the Archocentrus family you could put in more fish.
Oscars alone produce an enormous amount of biological waste. Not to mention they are a South American cichlid that thrives in a softer water. Central American thrive in harder water. I can guarantee that if you mixed them together the Oscar would pit out somewhere down the road.
Look at a seventy five gallon tank as being an excellent grow out tank, or for a single pet fish, or maybe a tank for a isngle pair of breeders. If you are going to use it for a smaller species like Neets, Nicks or any one of the Archocentrus family you could put in more fish.