View Full Version : Too much flow for a betta?

07-26-2010, 03:05 PM

I set up a 2.5g mini-bow tank in my daughters room. I set the tank up with a ac20 HOB filter and some seeded media. When we got to the store, she ended up wanting a betta.

I have never kept a betta, so I was wondering if the setup I am using has too much flow for the fish. I have the ac20 turned down all the way.

Thanks in advance.

07-26-2010, 04:36 PM
The best thing to do is to watch the betta's movements. Turn the filter off for a little while (enough to observe him swimming) and determine what is "normal" swimming for him. Then turn the filter on and watch if he gets pushed around by the flow or if he's acting abnormal in any ways. If he's having trouble, try to diffuse the flow a bit. I'm not familiar with the AC filters but on my tetra filter, I can just raise the intake tube to reduce the flow.

07-26-2010, 05:15 PM
When I had a betta, I also used an AC20. The fish was fine with the water flow. I often kept the impeller speed on the lower end since an AC20 is plenty of filtration for small tanks. Mine was on a 10g though. A 2.5 gallon with an AC20 might be overkill.

07-26-2010, 05:18 PM
Thanks for the replies...

I have an extra impeller, I think I will cut it down and see if that helps some. The betta looks like he is working a little too hard.

Michael Milligan
07-26-2010, 09:28 PM
What else is in the tank? lots of plants will cut up the flow and give the fish plenty of places to hang out.

And try putting some plants or structure right under the return flow. That will help a lot too.

07-26-2010, 09:33 PM
You could also you make a diffuser out of a plastic bottle. Thats what I did for my Betta's filter. I used a cut up gattorade bottle.

07-26-2010, 09:56 PM
An AC 20 sounds like way too much flow on a betta tank, even with a diffuser. I run an Azoo palm filter on my 2.5g and even turn down the flow on that for my betta. It's a great little filter and cheap, less than $10.

07-26-2010, 10:11 PM
Gotta go with lab on this one. Maybe if you had stream fish in that tank, the 20 would be ok but for a betta it is way overkill. Since most (male) bettas have long fins they really just can't fight with too much current. If you can't find an Azoo Palm Filter (they're hard to find in my area) you can always go with a small internal filter or a sponge filter as well. Bettas don't have too big of a bioload and since he'll probably (should be) the only inhabitant, a small filter will work out fine for him.

07-27-2010, 04:09 AM
Thanks again for all the replies.

I trimmed two of the impeller blades off and it worked like a charm. Now there is just a slow trickle when the AC is set on low.

07-27-2010, 05:36 AM
I trimmed two of the impeller blades off and it worked like a charm. Now there is just a slow trickle when the AC is set on low.

I had never heard of that solution before but it's definitely something good to know. I might have to do that to one of my own filters. glad it worked out :)

07-27-2010, 06:04 AM
Good luck.

07-27-2010, 08:59 AM
I put a sponge either on the intake tube, or at the outflow of the filter.
It's good to get some extra bacteria too (you never know when youmight need it lol!). Never knew the impeller blades could be cut to slow the flow either, good tip!