The slime you refer to could be fungus. I think you mix a teaspoon of salt per quart of water and put him in that. I would google that to make sure you use the right amount of salt. I think you can soak them in a stronger salt solution and then let it dry on them for a little while before putting them back in fresh water. You need a thermometer to accurately monitor the temp. I keep my hatchlings in about 2 to 3 inches of water with some fake floating plants so they can climb up to breathe. He should be eating reptomin and chopped minnows but if it is a fungus he may be off feed.