After doing a fish check in my tank yesterday i noticed 1 of my neons is really fat. It seems bloated and some scales are sticking out. i plan on taking water out of the 20 gallon and putting it in the 5 gallon so if he gets infection or something it wont spread. now how should i get his weight down? Should i not feed him for 2-3 days then start feeding him small amounts of food? What should i do?

if the scales are sticking out it could be dropsy, so you may have to treat for that. dropsy also 'fattens' them.

Its not dropsy its just fat. There are pecking orders with my neons and he is at the top so he eats alot. so now i need to know what i should do to him while hes in the quarintine tank.(how to get him back to normal size)

after the neon loses weight im sooo tempted to setup a planted tank! Im getting a hood and theromometer today.

Well i went to the store and got a hood, a thermometer, and 2 ottos! the ottos are cleaning up the 20 gallon now and are looking good. they will be moved to the 5 gallon when the neon is better.

If the neon were indeed just fat, then it wouldn't be sick (just in need of some exercise and less food). It sounds like it could be a bacterial infection. Dropsy doesn't always result in scales sticking out. Can you post a photo?

well, its a bit paler than usual, fat, and scales protruding. Its not eating anymore and stays by itself. the 5 gallon is running and hope to have it in there by tomorrow.