possible tankmates for convict?

I recently redesigned my tank and took out a lot of the tacky decor i had in it. Now it's looking a tad empty with just my two convicts in it. They have spawned once, i don't know if and when they will do it again, they're still a little freaked out by the redesign i did. I was wondering if there were any types of fish i could toss in there that wouldn't pose any problems for the pair.

thanks