Can a guppy live in a jar?

If you wish to be successfull keeping fish then follow the basic rules. :- 1 inch of fish needs a minimum of 1 gallon of water. :- Every tank needs a permanently running cycled filter. :- Every tank needs at least 50% of its water changed every week. Keep the above rules and your fish stand a chance. Anything less and I can guarantee that you will have constant health problems with your fish. Guppies are tropical fish and need a temperature of around 75F.