Originally Posted by dpints
i have a 2.5 gallon and was thinking of adding either a small cory or a small oto (whichever u can keep just one of). i have a heater but no filter. is this possible?????
Would advise against adding any more fish.Two and a half gallons is just barely acceptable for one betta.
All tropical fishes should be in filtered tank, any book written on tropical fishes will state as much.
Not trying to be mean, but adding more fish would be near certain death sentence for the fishes you mention.
Save up some money and get a twenty or thirty gallon. This will give you way more options and the fish will thank you.