They will eat anything that fits in their mouth. Size is usually 6-8 inches, occasionally a bit bigger. Like the "FW" moray eel, they do best in brackish or marine.
I kept mine in heavy brackish after he kept getting fungus in freshwater.
I found extra fish and problem. I don't know if it can swim with snakeheads 40cm long. I'm afraid about clarias, , they kill protoppterus(30cm) when they have 35cm. And I'vequestion about swiming? swiming a lot or stay?
in poland , if i find a predatory,rare fish is almost a miricle. Fine,rare are expencive. In grmany buing channna for example is normaly, , here is imposible
they can eventually be moved into almost complete freshwater even though it is not recomended you have to gradually condition them over to the freshwater though, and even then it is not complete freshwater, it is like blackwater or amazon water slightly salty and slightly acidic, ph of about 6.8 and just barely enough salt to be condisered brackish, hope this helps anyone!!!!!!!!!!