[Monster Fish]

It takes a long time for these guys to get big. They usually max out at 5-6 inches so they can go in a tank that's at least 110L. If you want to add appropriately sized tank mates, you'll need a bigger tank. Smaller upper jaw bichirs, rope fish, and butterfly fish are good tank mates for Ctenopoma acutirostre.

 

[Monster Fish]

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).

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