Always use a filter!!

[Shoebox_16]

I kept my male Betta in a heated 3 gallon without a filter - and within a few days my nitrites had gone up to 5.0. Yes, 5.0. And there was a film constantly on the surface of the water, which was like, thick when you put touched it

Never again

 

[night flight]

I believe an airstone and weekly water changes would work fine or a single betta in 3 gallon of water.

 

[Liam]

5.0. means nothing to me..?

5 ppm? 50 ppm?

5ppm isn't bad dude.

 

[Acer]

5.0. means nothing to me..?

5 ppm? 50 ppm?

5ppm isn't bad dude.

5 ppm nitrites is pretty bad to me...

A sponge filter would be alright for a tank that small with a Betta.

 

[FSM]

5.0. means nothing to me..?

5 ppm? 50 ppm?

5ppm isn't bad dude.

5 ppm nitrite is ridiculously high. You are thinking of nitrate.

 

[chesterthehero]

filter on a fish tank... huh.. whodathunkit

 

[Liam]

ah, sorry. misread.

 

[Cichlaholics Anonymous]

in that size tank even one of those small corner filters would work, no need for anything fancy

 

[Lupin]

in that size tank even one of those small corner filters would work, no need for anything fancy

Definitely!

 

[micstarz]

i keep bettas in 1 gallons with weekly waterchanges without too many problems - you might be doing some fatal overfeeding