Sick Red Eyed Tree Frog?

[ViperJr]

Not sure about the dark coloration, but you are overfeeding him. Growing RETFs only eat 2-3 crickets a night. Adults 2-3 crickets 2-3 times a week. He may have trouble digesting that much food. What's your temp and humidity?

Well, generally it's hard to actually overfeed red eyes, since they regulate themselves in their food intake. They very rarely get obese.

I have ordered a temp and humidity gauge for the tank and it hasn't arrived yet .. I try not to spray the tank too much because I don't want it too damp ...

It's not really want you want, but what the frog wants. Be sure to keep it moist, since the are from the rain forest of central America. Good thing you ordered the hygrometer, it'll make it easy to adjust accordingly.

I have a calcium supplement that I put on the crickets every second feed .. It's called Nutrobal

I'm not familiar with this supplement, but it seems like it contains both calcium and D3 (according to some good ol' googling), which is the two important ingredients. However, it seem to be made for tortoises, so I don't know if it contains anything unhealthy for the frogs, as I'm not so good at these kind of things. Someone else will have to confirm or deny that.

EDIT: You also really want more hiding space for the frog. Stress is a real health-killer when it comes to frogs, and red eyes are not the most stress-tolerant species. They basically want to feel safe, and they do that when they are amongst trees/leaves/etc. Remember that they also travel by climbing from branch to branch (or leave to leave, you get the point), so if you want it to be able to "walk around", you need more climbing space.