Just don't feed anything you found outside yourself, like worms or insects from your yard because they can carry parasites, disease, or other chemicals that can kill your fish. I once lost a 7" pim frontosa by feeding a 3" earthworm I found in my yard so I learned the lesson hard. I have had no problem feeding frozen shrimps, smelt, and other fish fillet so far. I just tear up the frozen food into bite size pieces and toss them into the tank. With regular WC and cleaning I don't have any problem with cloudiness from frozen food.