I would say that the reduced food supply is definatally an issue. If you want to take care of the puffer you need to find other sources of food. You may have to investigate frozen foods and fresh seafood options. But before you start new foods you should start improving the water quality so it does not get worse while you are trying new messy foods. Remember slow and steady changes should not shock your friend. Sudden changes will probably harm him. I hope that this helps.
