[AquaAurora]

If you bought what I think you did (this - this) also known as leopard gourami, spotted climbing perch, and mis-labeled by Pestmart as 'African leaf fish" (real African leaf fish) It will need 50 gallon minimum for itself so you are overstocked already. Don't get any torpedo like fish, that bugger can open its mouth a lot wider than you think and suck 'em down. Dwarf gourami may be safe.. silver dollar, tinfoil tetra, larger barb species, and other wide/tall fish might also survive, but again, going to be overstocked with that fish solo in a 25 gallon.
If your fish is not the one i linked first 2 images to.. then never mind my whole post ^^

 

[AquaAurora]

Yep its not a mean fish BUT it is a predictor and it WILL eat anything it can manage to fit in its mouth. Any tank mates you get now, make sure are bigger than him and will stay too tall/wide to be eaten as he grows.
I wanted to build a monster fish tank with my existing leopard sailfin pleco, one of these fish, a sexy datnoid (seriously awesome looking fish), maybe a bichir, and an arowana.. but take a lot of $$$$ to get a tank big enough for that monster group (min 6x4x4 foot tank), and a lot more $ for all the fish (no local sources gotta pay shipping x.x).

 

[AquaAurora]

If you can drive over to NY or NJ, you can find stores that sell the larger predatory fish.

I'll keep that in mind, though it will take a while to get enough $ for a monster tank (and to build a monster sump for it).