Flying gecko with anoles and house gecko in the same tank?

i have a 55 gallon semi aquatic tank with 2 anoles and 2 house geckos. 1 male and 1 female of each. they all get along fine. i also have some fish in there too, but they dont bother anyone. i am interested in adding a new gecko or reptile to the tank. i cant seem to find too much besides anoles, long tail lizzards and house geckos to add. i saw a flying gecko the other day but the store employee did not know too much about them. does anyone know if i can put a flying gecko in my tank? if not does anyone have any suggestions for me. id like to get something a little bit bigger than the anoles, but nothing that would hurt them. i have also looked at crested geckos but they seem to get a bit too big. if they are dosile enough then i guess they would be ok. i am having trouble finding answers so any suggestions, answers or links would be greatly appreciated. thank you for your input.