I am acquiring a fish that is on a diet of earthworms. So. When I go buy said earthworms, do I have to buy them specifically, or can I buy them live at say (Walmart) and just keep them alive that way? Would I be at risk for diseases or other complications? I would rinse off the poor worm before feeding. Then toss him to his demise. Any suggestions or alarms I should consider?? Let me know!!