READ BEFORE YOU BUY Dont believe the hype about these guys i have 5 in a 40 litre and they rock the world despite the hype they are vicous predators...THEY ARE NOT they will yes eat a dead fish and May catch a a slow moving guppy but no they wont eat fish so 95% of community fish are ok as long as they dont eat the crabs! Plants yes they do chop them up a bit but a proper diet of cucumber lettuce and proper invert pellets wil deter them but still add tougher plants Do need a land to dry off every now and again mix well with corryies etc... Do not need brakish water as long as you feed them proper invert food that keeps shells hard
As a teenager I had one of these in a very overstocked, algae-covered fully freshwater ten gallon community tank with no out of water area. It lived for two years, never leaving the water (although I would find it in my filter sometimes). It just ate whatever the fish dropped and carcasses and only died because it escaped one night and dried up.