Okay thanks everyone, great feedback! But as far as tank size goes, wouldn't 4-6 fish be a crowd? I'm very stern on giving all my animals a good home, and that includes my fish as far as space, and at that water quality goes.
By the way Ham, although I don't know binary I think I get your signature. Are two and 10 very much alike/the same in binary?
Okay thanks everyone, great feedback! But as far as tank size goes, wouldn't 4-6 fish be a crowd? I'm very stern on giving all my animals a good home, and that includes my fish as far as space, and at that water quality goes.
4-6 oscars would be a crowd! Seriously, though, it really depends on what you want to keep. While a convict and a Bocourti are both cichlids, adult size is very different.
I think you could add a few more fish as long as you give your Oscar and Severum space. I think the odd numbered fish theory is something that can work for schoolers, but once you go past 7 or 8 fish I don't think it matters. One thing to point out though. Any other fish besides the 2 you have planned will help to take the "focus" off each other, regardless of species. A school could work or another cichlid or two. either way, they'll keep the two from focusing soley on each other.
Good luck!
Just as an example, in my 150G I have ...
1 x severum
2 x uaru
1 x angelfish
1 x moonlight gourami
1 x tanginyikan eel
5 x bleeding heart tetras
and 4 x platies
By no means is this an overstocked tank. In fact I really like to give my fish enough room. As the uaru approach full size I might lose the gourami and a couple of platies to make room, but other than that there's plenty of room.
BTW, choose your pleco carefully. SOme grow into fat 18" monsters that deposit vast amounts of poo daily into your system. Many, if not most, are rarely active during daylight hours also. Perhaps one of the more active larger pleco species are the royal plecos (however, they are also serious poo machines !)
As you have a sev to start with, maybe also look at
chocolate cichlid
uaru
angelfish
rainbowfish
congo tetras
clown loaches
yoyo loaches
festive cichlid
Most of all, do your research. Some fish do much better as singletons in a confined space, such as a tank. Others really need to be in groups.
Have fun !
By the way Ham, what type of angelfish do you have, and would it get along with the oscar and severum generally? I've seen them before and liked them, I just always thought they wouldn't mix with cichlids or their pH levels.