I know you said they do fine together. But I thought Id give you some of my opinion. You shouldnt imo put a frog and a lizard together. Anoles are known for some aggression(males), and frogs contain mild toxins which can harm the anole. Both contain different bacteria and parasites which will harm each other(all animals have some parasites). I would keep the anole in a 20high imo, and same with the treefrog. To answer your question you don't need a pool of water for either of them unless you want to breed the frog. Just mist them daily. Anoles should have some plants in the tank which are leafy so the anoles could lap the water from the plants. Thats the only way they drink. You mist the plants twice a day. They drink "Dew" water. I used to live in their natural range. I found that out when I was going to my backyard(I was 9) and saw them drink from leaves. Both species are arboreal. Male anoles are territorial. To figure out if your anole is a male or not it will have a neck flap. Sometimes if you pick them up.... Before biting you they will flare that flap at you as a warning(let me go). Normally they use that flap to attract females and tell males(this is my turf!). Btw both have different care requirements and need different heat levels. IMO an anole needs a higher heat than the tree frog(which if your room is around 72degrees thats good for the frog). The anole IMO needs to be put in a tank with 79degrees-83degrees. Because thats the temps in their natural range(its higher but thats where they go into)