| I absolutely love Oscars too. I went back and forth with the idea of going for it or not... until I did. If you want a pair of those, with excellent filtration, you could house just a pair in a 4 footer 90gal tank (48x18x24").
However, if you have restrictions for tank size, consider a 30gal (regular filtration will do) or even 20gal (with very good filtration) and you could house two paired-off Convicts. Those are dark coloured cichlids, and grow up to 6" only; their parenting behavior is awesome; you might end up with a lot of fry but other than that...
Pepe
Santo Domingo |