I purchase a 1gal plastic "tank" (Resun PA-230). It's a back-up hospital tank I got for treating (short term) my injured female
betta with Methylene Blue (MB kills all beneficial bacteria). It served its use since she recovered well!
I left an airstone running in it, since I might use it to hatch artemia... or experiment with local Almond Tree Leaves properties (I picked up a few dry leaves today)... I don't think of any commonly available fish that could have a happy life in there... maybe a tank in which to place a carrying female Ghost Shrimp...
Pepe
Santo Domingo
I would just clean it, cycle it and keep a small sponge filter in it and let some snails do their business... It may come handy for emergencies.
Pepe
Santo Domingo