my friend has 2 fiddler crabs in a fresh water tank they are now 3 years old I want to get one and put in a tank I have a small tank it was origenaly for stupid hermit crabs if I put a slope in it and pit water in it and made it mor for ampidial animals wold it survive and I have a hermit crab under tank heater but I have no filter and the sunstrate is pure hermit crab sand and I fed it shrimp pellets would it manage to survive