Here's something I read...but don't necessarily quote it from me...I've only just searched through a few google searches for you:
Tankmates
It is important to remember that as with many out-and-out predators such as Arowana, Gars, Tiger fish (Hydrocynus sp.) etc. they rarely - if ever - molest their tankmates. It's usually the other way around. Fish to avoid would include aggressive Central American cichlids such as Vieja sp., Nandopsis, and perhaps even the Oscar.
Good candidates include large Tinfoil barbs, Polypterus, Synodontis sp. and other large characins, basically most large, non-aggressive fish.
The African pike characin
Hepsetus odoe
Size: There is a fair amount of conflicting opinion as to the eventual size of the species 60cm/24" long being one of them - and while this is quite possible, in my experience I have never raised one any larger than 30cm/12".
Guide price: I think the last one we had for sale in the shop was in the region of �30 for a 6" fish.
Aquarium care: The minimum size tank for a single fish would be 120 x 45 x 45cm (48" x 18" x 18"), and 180 x 45 x 45cm (60" x 18" x 18") for a couple. The best set-up includes plenty of cover in the way of plants, driftwood, etc. Standard, fairly bright lights will be fine, so long as you provide them with cover so they have a good sense of security. Avoid any sharp tank d�cor.
This is part of what I found....you could try googling and reading about it too.