I have a 5 gallon sitting around. I don't want to buy another heater so I came here wondering what I could stock it with. I want like a fish and some snails, maybe a few shrimp. Any suggestions?
The only thing that you can put in there without a heater is probably a tadpole along with a couple of pond snails.
And no goldfish, goldfish get to be up to 8-9 inches long and need a 20 gallon for one adult and another 10 gallons per adult. The only way to put goldfish into that tank is if they were fry.
It is highly recommended to have a heater in order to keep the temperature from fluctuating (even by a little amount)... A betta is a tropical fish that would be best to have in a water temperature of 78F or so.
FYI, my coldwater tank is currently at a temperature of 66F... I'm pretty sure that a betta will not be able to live happily in an unheated tank at my house :S... It all depends.
*** Whoops, forgot about the size of the tank... Fluctuations in the temperature can easily happen to a small tank as there is less water that needs to be cooled off or heated up.