Ok, so my puffer hasn't gone to the bathroom for the last couple days. His stomach is bloated (he hasn't eaten anything the last 2 days) and when I cleaned the tank today there was no BM to be found. Should I not feed him and wait a while or is there something else I should do? His colors have changed lately too. Normally he is lighter on top with a white belly. Lately he's darker which makes me think something is wrong.....