The Puffer Forum

Against my direction, my friend gave a single piece of mozzarella cheese (one shredded piece) to my 1.75" GSP. The GSP literally devoured it in 2 seconds. I immediately looked online about the dangers of feeding fish cheese, and came upon a single thread on yahoo questions where people warned against it, and in one case, explained that it will kill the fish.

Can anyone provide any insight? I'm worried. The cheese obviously has lactose, fats, and all kinds of strange things that a puffer would never eat. So far - the puffer seems fine.

I doubt highly that one piece of cheese will hurt him but be sure to stress it never happens again. Puffers need crunchy foods, like snails, mussels, clams and etc. I don't think cheese is one of their natural prey anyways.
Check out the article in the librabry on Green Spotted Puffers and also the feeding article that is in there.

One instance shouldn't be a problem. Just be sure to heavily "suggest" that your friend doesn't feed your fish random food. That, or get a new friend.

Personally, any "friend" who ignores me when I tell them not to do things that bother me gets reprimanded, but I'm also highly temperamental when it comes to people doing things I hate.