I wouldn't be worried over 5 days, but if you're going to put something live in the tank for it to go after, I wouldn't recommend goldfish or any other fresh water fish. Try smaller ghost shrimp or small feeder crabs. You might want to also try silversides or other chunks of meaty foods on a feeding stick. It would be best if you could find out what/how it was being fed from wherever you purchased it from.