Yes bettas can live in a filterless tank/bowl but sometimes you get tired of having to clean his tank every week or every other week. I have several tanks of varying sizes and decided that anything over 2 gallons needed a filter.
I saw the air filters (have a sponge that your air tube fits into). These claim to be able to filter different size tanks and they were cheaper than other filters like the bio wheel and the whisper filter, so I thought I’d give them a test drive and report my findings back to the site.
I didn’t purchase one for my 2 gallon hexagon tank that “Z” is in and I did not get one for the 3 gallon tank that “Jack” lives in. I did buy one for “DOS”, who is in a 3 gallon tank and I bought one for my 10 gallon tank. Total, I spent right under 20 US dollars.
The air filter I got (not naming brand names) for the 3 gallon tank had a plastic cover with suction cups and the filter card fits inside of it. The air tube slides in behind the filter card causing a suction into the filter as the air blows bubbles.
The filter I bought for the 10 gallon was a large sponge that fit in the corner of the tank and the air tub slid into a larger plastic tube in the center of the sponge.
They were easy enough to fit together. The corner filter was easiest to install because of the suction cups that attach the plastic cover to the side of the tank. The large sponge for the 10 gallon was harder to get in place because it continually want to float to the top.
After getting the sponge to stay down, it was relatively quiet. The 3 gallons filter was not quiet at all.
The 3 gallons air filter works very well for this size tank. The only problem I have with it is that the plastic cover can come off and I find myself putting it back on at least once a week. However, I only completely clean the tank 1 time a month and change the cartridge 1 time a month. The filter cartridge does have debris on it and I feel it is effectively cleaning the 3 gallon tank. I do not think it would be as effective in a 5 gallon tank.
The corner filter in the 10 gallon found its way to my trash can. It never had debris on it and my water slowly yellowed after 2 weeks of use. On the package of the filter it stated that this filter would be good up to 20 gallons. I do not even know if it would work in a 5 gallon tank – more than likely not. I noticed right off that this thing didn’t even have enough suction to move the bettas fins downward when he swam over it. Heck, he liked to sleep on it!
Remember, this is my personal experience with these filters but I can assume that results would vary very little from my test drive of these two types of air filters.