Welcome to Frog Forum Sobo! You got good information from Jessica & Grif. As stated by them; the moss got to go ASAP. If frog was in a box for 5 days would recommend to try and get it eating soonest. Small Pacmans like that need food daily.

Spring water is fine; tap is OK too as long as you use a conditioner (removes Cl, chloramines, and heavy metals). Distilled, de-ionized, or R/O water are not good and will harm your frog. If you live near a Petsmart; check out the hermit crab water dishes. They have a very small one that sells for 99 cents and it will fit in a small critter keeper and serve as a soaking dish for small frog.

Remember to wash your hands and rinse them with dechlorinated water before handling your frogs. It's a good idea to wash them again after done handling. Good luck!