I HAVE A 30 GALLON TANK THAT I KEEP MY THREE ALLIGATOR SNAPPERS IN. YOU NEED TO HAVE LOTS OF LEDGES, PLANTS AND LOGS SO THAT THEY HAVE SOMETHING TO CLIMB UP ON TO GET TO THE SURFACE. IF YOU DO NOT IT WILL REALLY STRESS THE TURTLE SINCE THEY REALLY CANT SWIM. ALOS HAVE LOTS OF GAMBUSIA OR GUPPIES FOR THEM TO LURE IN. KEEP CLEAR OF GOLDFISH IF POSSIBLE, A LOT OF THEM HAVE BEEN TREATED WITH COPPER CURE AND THIS REALLY IS NOT GOOD FOR TURTLES. I HAVE A 150 GALLON READY FOR MY TURTLES WHEN THEY ARE A LITTLE BIGGER.