I've been using one of these in a 2.5 gallon for quite some time.
http://www.drsfostersmith.com/produc...1&N=2004+22769

Azoo Palm filter, designed for tanks 5 gallons and under.

--
-----
Billy
-----

-----
"Larry Blanchard" wrote in message
...
| I've currently got a betta and a cory cat in a 2.5 gallon tank with
no