I was thinking a few angels might be nice
The only thing I don't like about yellow labs is that they are fairly common and when I bred them I couldn't give the fry away. If you like yellow fish then you might be able to make Leleupi work in there, again probably a situation where you want to start with 6 small ones and let a pair form, then sell the others back. They are a little larger than brichardi type fish and a lot more agressive, but it could work.