On the other hand, rice paddies and river basins in Southeast Asia represent a Betta’s natural habitat, with little to no moving water. Water movement can effect its swimming, as its large, heavy fins act as sails and it is a slow swimmer also, especially the long-tailed varieties whom suffer from being dragged by the current or trying to swim against it, causing a lot of stress.
The following filters are suitable for Betta fish and will not cause them so much stress:
Sponge filters are the oldest type of filter used, bearing the great advantage of being powered by water pumps, thus giving you the opportunity to adjust the water flow.
Many aquarists think this type of filter requires too much space or is unattractive, but this filter has no dangerous inlets that can suck up young fry, which makes it the best for betta breeding tanks.
Under Gravel Filters
Like sponge filters, under gravel filters are powered by a water pump. Though they work with a powerhead, is not recommended, as power heads create too much water movement that can prevent free swim.
If using an air pump, you can get a cheap valve and adjust the water flow so your Betta will not be disturbed.
Many canister filters have controls for water flow, which is very helpful when you have a Betta. This is a great opportunity since Bettas cannot swim against strong currents.
As so many models are available on the market, you must make sure you choose one with adjustable return flows and is designed for your tank dimensions. The only disadvantage with these filters is the high cost compared to other filter types.
It has been debated if these filters actually work for Betta tanks or not considering most of them have strong return flows, which can effect Bettas swimming and stress them a lot.
The advantage is some models have bio wheels that help dissipate the return flow and also give beneficial bacteria a place to develop.
Reduce the filter flow
If you already have a water filter that might be too strong and does not allow you to adjust the water flow, you can always reduce the flow yourself by using these hacks:
A baffle may be anything blocking or redirecting the return flow, thus helping the fish feel more comfortable. It’s very easy to make it yourself by using the mesh screen from a cheap tank divider kit. You can cut it in a narrow strip and place in front of the filter to dissipate the water flow. You can also place a soap dish in front of the water outlet to slow down the water flow, but be careful to use a clean dish, as those that already held soap may be toxic for the fish.
Create an oasis
Plants and decorations may reduce the water flow or create barriers to make the fish feel more secure. They also provide hiding places and make your aquarium look more beautiful.
Block the intake
You can do this by using pantyhose. Actually, Betta keepers have been using this method for a long time in order to reduce the water current. Take a piece of pantyhose and wrap the filter intake in it, then secure it in place with some rubber bands. This not only helps reduce the water flow, but also helps reduce damage to the Betta’s sensitive fins.