Snails are terrific poop producers and need 2.5 gals. of their own. I wouldn't try one in that small of a tank.
It sounds a perfect size for your betta. Put some pretty plants in there (live or silk) and you're good to go.
My dude has taken over a 5 gal. all to himself. He bullied a snail and I had to remove it. LOL. I'm afraid to try anything else with him. I got a small clay pot and "planted" some java fern in it with some gravel. It's cute looking and my betta likes to lay in it. Plus I've got silk plants.
Well thank you guys very much. I decided to let him have the three gallon to himself (though I almost got a bumblebee catfish) I might introduce an oto later depending on whether the tank gets algae or not.
I'd suggest not getting the otos. They like to be in groups also. Algae can be prevented by good water maintanence and not leaving the light on too long. Fish should never be relied on to clean the tank. If you do get algae then you can simply clean it off.
don't forget King, that if you add an oto, it will be very lonely in there all by itself, and won't be very lively, so you might want to consider another bottom dweller (even though oto's are awesome catfish).
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