Hi omega59 
If your jar can hold 2 gallons, it might make a fine home for a couple of African Dwarf Frogs.
These are miniature aquatic frogs that take up very little space and are very cute. They do best without filtration; just regular water changes and tank cleanings, and do need to be kept in a covered container to keep them from jumping out.
Just be sure you get African Dwarf Frogs and not African Clawed Frogs which grow a lot larger.
If your jar can hold 2 gallons, it might make a fine home for a couple of African Dwarf Frogs.
These are miniature aquatic frogs that take up very little space and are very cute. They do best without filtration; just regular water changes and tank cleanings, and do need to be kept in a covered container to keep them from jumping out.
Just be sure you get African Dwarf Frogs and not African Clawed Frogs which grow a lot larger.