I have my sub-adults in 32 Qts and my breeder size females in 60 Qts (they are the Sterilites with the wheels, I just popped off the wheels) and I love them because they have enough room to stretch out, with out it being too big for them. A couple of my girls are 2500-3000grams and would be like sardines in a 41Qt. I have big dogbowl waterbowls in there for them so they can soak, and its enough length that there is a definite hot side and cool side.