Adding pygmy cories

[I_Smell_Fish]

I've had my betta in small tanks with other fish before. No problem with carefully selected fish. I don't remember what type of filter I had then, but I've gotten a 3.5 gallon tank and have put a betta and 6 pygmy corydoras in it and I can't find a filter slow enough for the betta. They are all too strong.

Do you know of filter than will work in a 3.5 gallon tank? Not an "up to 10 gallons" filter. Those are too strong.

Do I need to remove the cories if I can go without a filter?

Thank you

 

[Essjay]

I would remove the cories because the tank is not big enough for them (minimum tank footprint 18 x 12 inches, 45 x 30 cm), and because bettas prefer warmer water than pygmy cories. Pygmy cories are also a species that seems to do better with more of them than is usually recommended for cories and there won't be room for 8 to 10 in a tank that size.

As for a filter, try a sponge filter powered by an air pump. That's what I use in my betta's 26 litre (7 US gall) tank. I have a splitter in the tubing which I use to control the amount of air going through the sponge, and this controls the water flow rate.

 

[FroFro]

I've had my betta in small tanks with other fish before. No problem with carefully selected fish. I don't remember what type of filter I had then, but I've gotten a 3.5 gallon tank and have put a betta and 6 pygmy corydoras in it and I can't find a filter slow enough for the betta. They are all too strong.

Do you know of filter than will work in a 3.5 gallon tank? Not an "up to 10 gallons" filter. Those are too strong.

Do I need to remove the cories if I can go without a filter?

Thank you

Just to add, 3.5 gallons is way too small for a betta. The minimum size needed for a betta is 5 gallons. Just because a betta can survive in a tiny tank does not mean they thrive.

 

[I_Smell_Fish]

k

Thank you. That is good advice. I've never had a betta in this small of a tank at 3.5 gallons. I bought this one because I was told it was 7.5 gallons. I'm buying him an established 5 gallon tonight. Can't wait to put the little guy in it!