How many could live in a 10 gallon tank? How quickly do they breed? If I get a male and female will I soon have a tank full of babies:/ ? Can I have a tank with just males or just females? Do they ever fight? Will they need a heater or will they be fine at room temperature? What substrate should I use? Can I just use sand or newspaper? Will they die if you drop them? How active are they? When are they most active? Do they make good pets? Is there anything else I should know?