Do Betta Fish Prefer Long or Tall Tanks? (Answered!)

It is easy to see why Betta fish are so popular in the freshwater fish-keeping hobby.  These colorful, hardy fish have bundles of personality and soon become true wet pets. If you are new to Betta keeping or thinking of upgrading your existing Betta tank, you may be wondering do Betta fish prefer long or tall tanks?

My experience of keeping Bettas for over 20 years tells me Bettas prefer long tanks rather than tall ones. For Betta fish surface area is more important than water depth, so the longer the tank, the greater the surface area.

Do Bettas prefer long or tall tanks?

For almost all the fish we keep in our aquariums, the surface area is far more important than the water depth.  

The greater the surface area a fish tank has, the greater the area that can effectively allow gas exchange between the water and the air.

At the surface of the water, carbon dioxide is released from the water into the air, and oxygen is absorbed into the water.  The greater the surface area, the more oxygen can be absorbed into the water. Therefore, the greater the surface area, the more fish we can keep in the same volume of water.

Both the tanks in the images above hold 40 gallons (150 liters) of water, however, you could keep considerably more fish in the rectangular tank than the column tank.

Bearing all the above in mind, a long tank would be better for a Betta than a tall tank.

Do Bettas like the extra swimming space of a long tank?

Again, in my experience, I think Bettas do prefer the extra swimming space a long tank gives them over a tall tank.  In my fish room, I have Bettas who like to swim back and forth, taking full advantage of the tank length, but I also have one or two who are too lazy to swim very far.

It very much depends on the individual Betta, but I would still go long over tall every day.

Other advantages of a long tank over a tall tank

As we know, Bettas do not like a lot of current in their aquariums. The problem with a tall tank is the return from the filter can create a cyclone effect, swirling the water around, whereas the same filter in a longer tank will create a slower flow, and there will naturally be more places in the tank where the Betta can get out of the flow altogether.

The final advantage a longer tank offers over a tall tank is stability.  It is much easier to accidentally push a tall aquarium over than it is a long aquarium.  Although at first glance you might not think that would affect the Betta, it would if his tank was knocked over and he ended up on the floor!

My final thoughts on ‘Do Betta fish prefer a tall or long tank?’

From experience of both Betta keeping and fish keeping in general, I would always say fish prefer a long tank over a tall tank.  

I can’t think of a single species of fish that would do better in a deep tank that had a very small surface area rather than the other way around.

One of the most critical parts of keeping a fish alive in captivity is having enough oxygen available in the water, and the process of dissolving oxygen from the air above into the water relies on the surface area.