AnyOne ever used ParaZap before? & FatTail Question

[DirtyDuck]

Purchased a male fatatail gecko from petco about 3weeks ago and it looked nice and healthy and had a Plump tail. The employee told me that they have had the Fattails for a long time. I set him up in his new home waited a day to feed him and he didn't eat. I gave him Mealies,Wax Worms & Crix. this went on for about a week then I bought some reptile appetite stimulant and he ate a few crix the other day, but he had very little poop and It was green & kind of smooshy. I can't really get a good stool sample to take to a vet so I Bought some ParaZap I sprinkled some over some crix, but the ParaZap has no instructions so I don't know how long to give it to him? A guy at the local petstore told me that FatTails are notorious for going on hunger strikes when they move to a new home, is this true? It looks like his Tail has lost a little weight to.