Wait, what's going on? Are you going to put the two firemouths and a JD in the same tank?
How about leaving the convict pair in the 29, deciding between the JD and the firemouth pair (because I have to agree with people who say a 55 is too small for a full grown oscar, which are most people here and on MFK), or going with something smaller?
I don't mean to be rude, but I think that I and everyone else could help you more if there was a little more coherence in your typing. I'm not trying to be a grammar/language nazi, but I do think it would really help.