Never feed cooked food to your fish. Cooking denatures (chemically changes) the protein structures and can make it very difficult to digest. Fish can't cook their food (that whole fire/heat under water thing..) and shouldn't be given cooked foods. Sometimes tiny amounts are OK but for a staple it's not good. Think about humans, we evolved to eat cooked food, imagine what would happen if you ate a belly full of raw beef...your body wouldn't be used to it and, even though it wouldn't kill you, you wouldn't feel too well for a few days. A few good examples of denaturing protein is cooking eggs ans pickling meats. Egg whites (mainly consisting of the protein albumin) start off as clear and as heat is applied the protein structure changes making the "whites" opaque. Pickling meats has the same result, you expose the proteins to acids (vinegar) and the protein structure changes visibly (turns whitish).
Be sure to soak all his foods in Selcon & a good marine vitamin supplement.
http://www.**************.com/forum/library/category/feeding/
You may also have to treat your puffer for IPs if he doesn't put on weight very soon with a good diet.
http://www.**************.com/forum/library/hospital/internal-parasites-prevention-and-treatment/
I hope he's in QT!
http://www.**************.com/forum/library/hospital/qtine/
I'm not sure why you didn't pick out a healthier specimen?
