I had a male and female Belonesox (Pike Topminnow) mate in a 20 gallon long. The female died of complications in birth. They are livebearers. I was able to salvage 13 fry before the became munchies for the other fish. As stated before, as fry they are extremely cannabilistic.
I had to act quick and placed the 13 fry in a 1 gallon plastic critter cage before finally setting up a tank for them a few months later.
They are said to be extremely picky eaters and only take live food, but I have been lucky in raising them from mico-fry and have mine trained to eat any type of finely cut meat from a plastic spoon that they take turns swimming right up to and snatching greedily. Awsome little fish. They are very slim and skittish. No way that they survive an oscar.
They can go brackish, and do prefer at least some salt. Again this puts them out of water parameters with most any S/A cichlids.
Other livebearers (adaptable to salt) work well with Belonesox. The adults had no issues being kept with freshwater flounder. I keep mine in a mixture of 1 heaping tablespoon (not teaspoon) of marine salt per gallon of water. This is still well below brackish at ~ 1.002 S.G.
