ok i halfed the tank but gave the big one more space and im using a hot water bottle wrapped in a small towel under the mulch for the big one and kept the light on the little ones side . but he was taking chunks outa the dog food a couple minutes b4 i seperated them but thaught i should anyway just incase the little one is male and im not feeding it vegies yet untill it gets used to eating more of the dog bicks so then i slowly sneak the vegies in i mean u know kids some times u gotta trick em