Filter too strong for new betta


How to reduce filter current/intake?

I decided to set up an old tank I had in the attic for a betta fish. Unfortunately I threw away the old filter that came with the tank, so I bought a new filter for the tank, Tetra Internal Power Filter. I went with Tetra since the old betta tank also had a Tetra filter, however it was different. My old filter had an air pump (or is it called an air stone?) that was kept outside of the tank and was attached to the filter by a tube. And that filter had an adjustable nozzle to adjust the flow. However, the new filter does not have a separate air pump, and instead the power is internalized. I thought this was awesome, as I wouldn't have tubes and wires messily hanging around. I setup my aquarium and the filter, and thought it seemed pretty great- that is until I got my new betta fish yesterday...

Since being in the tank, my betta seemed to be struggling to swim and could not stay in one place. In fact, I haven't seen him rest once since I got him. I assumed at first it was due to him not being a strong swimmer yet from being in a cup for so long. However I realized that his labored swimming was due to the filter! I decided to unplug the filter, and immediately he seemed relieved and slowed down and began resting.

I can't return the filter, are there any suggestions on how to reduce the filter current? I know about the water bottle trick, where you place a cut water bottle under the flow to ease it, however how can I reduce the intake? That's my biggest question.


What you're attempting to do is called baffling. The easiest way to slow the actual intake is to put something in front of it like fake plants or decor. You can attach something like a sponge to it but I would advise against this method. By slowing the intake the filter is essentially working at max capacity but getting half the result. This can put a lot of strain on it and may affect the longevity.

The intake really shouldn't be the main problem though. Those filter intakes aren't strong enough to cause issue unless the betta has very long fins and is directly in front of it.

Your previous filter was likely some sort of sponge filter. The device was an air pump, an air stone is something you attach to a pump and put into the tank. It releases a bunch of tiny bubbles.
  • Thread Starter


Thanks, yeah I thinking to use a water bottle or a sponge. And it actually is the same type of filter as the old one, uses the same cartridges and everything. (And the air thingy was an air stone, the old tank came with a bubbler and both the bubbler and filter attached to the air stone.) I was reading reviews for the filter I bought, and although the reviews are overwhelmingly positive, betta fish owners said the intake killed their fish when their long fins get tangled inside. And there is a recommendation from Tetra to use a stocking (some people call it pantyhose) and tie it around the intake. I did this and the current in the aquarium seemed to ease a bit. But I'm still going to try the water bottle or sponge idea, thanks!
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