Buy one of those critter cages or reptile cages, they have a 3 gallon one and put a splitter. It cost only like $10. You could even hook on a tiny filter. If your house/room does not drop below like 75 degrees you could do without a heater. Even 72 is tolerable for a short time. Try adding some real plants too like java fern and some type of floating plant they love that.