Intelligent fish for a walstad tank

Well...any thoughts? I was planning on using a 25 gallon storage bin that is 35 inches long and 16 inches wide, with about 7 inches of water depth (the bin itself is 13 inches high but I am leaving it half full partially to stabilize the bin and partially to allow for extensive emersed growth). I would love it if the fish was relatively easy to breed, and would especially love a dwarf cichlid of some sort. Thankx!