Hello everyone, I have an issue and I would like to know what you all think. I have 2 African Dwarf Frogs and they are currently in a 2 gallon tank. From the research I have done, the water is supposed to be at least 70 degrees. I know for a fact the water they are in now is not that warm. What do I do?? Do I need to buy a tank water heater??

Please help, it is visible that they are cold, they wont move at all and they will not eat. They haven't eaten in almost 2 weeks, I don't think its the food because they have eaten it previously.