I really want to make a shrimp bowl/jar "aquarium" for cherry shrimp and other Neocaridina but I live in the uk and my tanks get cold without a heater, and I have no idea on how to heat the bowl/jar. I could buy a Nano heater, but i think that would be overkill. I was also thinking I could place several jar/bowls on a reptile heat mat, but I'm not sure. What are your suggestions, and what do you think I should do?