i wouldnt put anything other than perhaps a shrimp or two or three in a 2.5g with a betta. cory cats are very social fishies and need company of their own to feel secure and healthy. probably 6 or more??
what all do you have in your big tank??
Chris- Husband, 04/30/77
Cailyn- Daughter, 07/05/99
Jeffrey- Son, 03/24/06
Alex- Son, 03/25/09
Mister- Black LabX, M, 08/06(?)
The Shadow Stalker- Gray Tux DSH, M, 04/04
The Mighty Hunter- Black Tux DSH, M, 04/04
Baby Girl- Tabby DMH, F, 12/03(?)
Frances- Tortie, DSH, F, 2007(?)