Sometimes a pair of Carpintis can be totally fine in a community. I had a pair that laid eggs all the time in a very cramped 90 Gallon, and they didn't bother anybody that stayed away from their cave. But, sometimes, they can be real aggressive in a community. I think 3 10-12 inch cichlids in that tank would be fine for life. I think there's a chance that a pair of Carpintis with another cichild or two would be great. You might also consider a Chocolate cichlid, or a Synspilum. Ya just never know until you try it out. If you have JUST the ONE Carpintis, that would be easier--less drama without breeding going on. Maybe a GT, a Carpintis, and one or two of -- regani, chocolate, severum, sajica. Sajica would go GREAT in there. Get 4 Sajica and try to get a pair of those, they're less aggressive, even when spawning. They grow really slow like a GT does, they look GREAT when they're adult, and they're hard to find so if you got fry people would love to have them.