One of the most important decisions when setting up a new Betta aquarium is whether or not to have moving water. If you do have moving water, how fast should the flow be? This is a decision that can have a long-term effect on your Bettas’ health and wellbeing.
Betta fish have evolved living in slow-flowing bodies of water. They are naturally found in slow-moving streams, ponds, and marshes where there is little movement and currents are gentle. Betta fish do not like fast-flowing water. Bettas kept in aquariums with fast-flowing water or strong currents may become stressed and can actually die of exhaustion.
Do Betta fish prefer still or moving water?
To best answer this question, we need to look at where Bettas naturally live in the wild.
Betta fish have evolved to live in shallow marshes, ponds, and slow-moving streams. None of these natural water bodies have a high flow of water or strong currents.
Over the last few centuries, wild Bettas have made paddy fields their home. These flooded fields are shallow and have little to no water movement.
In our aquariums, it is important to try to recreate the Bettas natural environment as closely as possible. If we place Betta fish into an aquarium which is a whirlwind of water movement, the Betta will be very unhappy and will quickly die from stress.
The captive-bred Betta fish we keep in our aquariums today have been bred to have longer, more flamboyant fins than their wild cousins, and as such are not strong swimmers.
If a captive-bred Betta is kept in an aquarium with a strong flow, it will struggle to swim against the water.
Can Bettas live in water with no flow?
Whilst Bettas like very low flow, having no flow will be bad for a Betta tank. A Betta tank must have filtration and filtration by its very nature requires flow.
If we keep Bettas in aquariums without any filtration, the Betta will soon become overwhelmed by ammonia from its own waste. Ammonia can kill a Betta in a very short space of time, and can also lead to the Betta becoming stressed, which in its own right can kill a Betta.
Having no flow at all in a Betta aquarium will also lead to a build-up of proteins on the surface, resulting in an oily film forming on the surface of the water.
How much flow does a Betta tank need?
How Much flow a Betta tank needs is very hard to quantify. In my experience, the flow from an air-powered sponge filter or a small hang-on-back filter offers the right amount of flow. I like to use this hang-on-back filter which I ordered from Amazon.
The filter should provide enough flow to move water around the tank, but not so much that the Betta struggles to swim against it.
It can sometimes take a bit of trial and error to get right.
What to do if your Betta tank has too much flow?
Sometimes the filter on a Betta tank is just too powerful and creates too much flow. In these circumstances, there are a few things you can do.
1. Adjust the flow rate
If your filter has an adjustable flow rate, just turn it right down so the flow is at its minimum. You might need to turn it up a bit over time, but start at the lowest setting and work your way up until you find an output speed that works for your setup.
2. Direct the flow
If your filter has an adjustable nozzle, direct the flow out of the filter against the back wall of the aquarium, that way the flow around the tank will be reduced, but the filter should still be working efficiently.
3. Restrict the intake
If you are unable to restrict the output from the filter, you might be able to restrict the intake. By adding a small piece of sponge over the intake, the amount of water the filter can draw in will be reduced, thereby reducing the output flow at the same time. There are a number of different intake sponges on Amazon, so you will probably find one for your filter.
The video below has some more suggestions on how to reduce the flow from a filter.
My final thoughts on ‘Do Bettas prefer still or moving water?’
Betta fish like their water to have a little movement, but not so much they can’t swim against it. If the flow is too high, the Betta will become exhausted swimming against it, if the flow is too low, the water may become stagnant and develop an oily film on the surface.
Taking time to get the flow right can make a huge difference to your Bettas well being.