So, i'm relatively new to owning anything other than dogs and small rodents. I have a Bearded Dragon who is a little over a year old, but that's the extent of my experience in that regard. I was introduced to Red Eyed Tree Frogs and i would really like to own one. I've done some basic research, i had a habitat all set up, and I brought one home early yesterday. I woke up this morning and he/she did not survive the night. I'm trying to figure out what went wrong.

A little about my set up: i was told that a 20G long tank was fine, so that's what i used because i had one. I cleaned it with water, let it air dry, then set it up. I used coconut fiber substrate with some moss, set up a shallow water dish, added some fake plants. I set up lighting - a day basking bulb and a red night basking bulb. I added the frog. The temperature when i went to bed was just below 80 (thermometer closer to the bottom of the tank) and had been consistent since i set it up. Humidty was around 70. Everything was misted and moist. Frog was happy under the basking light. Next morning, he was gone.

I don't know what i did wrong. Did i miss something? Can anyone think of anything? I'm hoping for some tips so that i can set up a habitat and eventually get another frog. Would a different tank be better? A lot of people like the 18x18x24 vivarium kits and that's what i see more commonly used, so i did order one just in case. Am i using the right lights? Should i ditch the basking lights and just use a low watt ceramic heat bulb on a thermostat? Do i need a UVB light? Wrong substrate? Any ideas?

Also, where did everyone get their frogs? Mine did come from a pet store (i know, not a good idea and may be why it didn't survive, but i thought it would be better to see what i was getting and the frog i chose looked perfectly healthy and cared for properly so i went with it).

Please no judgement - i'm trying to learn from any mistakes i may have made. I feel really bad.

Thanks in advance!