A 29g would be a great tank for the herps I am currently keeping, which are crested geckos and tree frogs! Cresties are cool looking, arboreal, fairly active, and dont mind being handled. The tree frogs are nocturnal, yes, but are surprisingly interesting to watch! Buy a low wattage red bulb, or a regular bulb with clear red plastic wrap over the fixture, as the frogs cannot see red light, and they will think its night and you can watch them easily! For species i would recommend either whites tree frogs or green tree frogs.