Newt won't eat!!!! PLEASE HELP ME!!!!

[Dow]

I have four firebelly newts. Three are complete fatties and eat any and everything they can catch (or kill it). this list includes 1 crested betta, 1 half moon betta, 1 delta betta, 3 fancy guppies and a glass cat. Yet they leave the african dwarf frog alone. HOwever, I have them in a 10 gallon tank with feeders, a reptile hammock and a stick to lead out of the water. Every week, what guppies they haven't eaten, I'll catch and chop up and watch the feeding frenzy commence. Well, when I got the fourth, he was in poor condition from a whole in the wall fish shop. He was skinny and lethargic but with vibrant color and reactions. But he cut his foot a few days ago and he won't eat or even go in the water! He's drying out, so I spray some of his tank water on him. I've even isolated him in a smaller tank with food. Shrimp, brine shrimp, guppies, chopped up guppies... Nothing works!
He's nearing death!

[Kittysnax]

could be a number of things. Too cold, parasites, fungal/bacterial infections, etc...Its hard to say. I havent kept fire-bellies in a good 7 years, so I dont know whats on the market as far as medications go, but Id round up something to combat infections. He is probably lethargic from the cut, but its hard to say as I didnt purchase him or know the entire story :<

But I'd just go: clean water>medication>warmth=possibility of a bounce back?

[Dow]

I've cleaned the tank, put new moss in, complte 75&#37; water change, washed out the gravel ((Keeping some as a bacteria supply of course)) raised the tempurature to it's normal 78, tried dripping dechlorinated ice water in to cool it down. Maybe he's just bruminating but it's kind of worrying me because he'd bounced up and was looking healthy right after I bought him from his dingy little tank. i've got him in an iso tank right now.