do otos and corys need a filter?

[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?????

[1077]

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.

[ThePearlFish]

In addition to a 2.5g pretty much being suitable for only one betta, corys and otos like to live in groups of 3-4 or more. A suitable tank size for a betta and 3-4 otos or corys at the very least would be 10g. Plus, a 2.5g costs around the same price as a 10g in some stores, so you would get a better deal :) or you could just enjoy your lovely betta in his own 2.5g. he won't suffer without any companions :)