Gourami Swimming up and Down Glass? Here’s What It Means

Last Updated on February 22, 2022 by cmoarz

If you’ve recently gotten gourami, or maybe older gourami that is displaying this new behavior, It is something you should be concerned about. Here’s what it means and how to fix the problem.

Gourami swimming up and down glass is a sign of stress

Lots of fish take part in what’s known as glass surfing, where they “surf” up and down the sides of the glass aquarium. For many species, such as corydoras, It’s a good sign. It means they are playing, and in some cases, getting ready to spawn.

However, In other species, it’s a sign of stress. Gourami, particularly dwarf gourami (Colisa lalia) are known to do this when they’re under stress.

Among other things, it’s usually caused by water conditions (usually related to ammonia and nitrites), overcrowding, or harassment/predation from tankmates.

For newly added gourami, This often happens for the first few days as they get adjusted to their new environment. Then, they go back to normal behavior for the most part.

However, If it continues after a few days or they begin surfacing at other times than when initially introduced into your tank, It’s likely due to stress and you’ll need to take steps to remedy the problem.

How to Fix Gourami Swimming up and Down Glass

First, check your water parameters. Is there ammonia or nitrite, over .50 ppm? Is the nitrate concentration nearing or exceeding 20 ppm? Are you using a dechlorinator?

The first thing you always want to do is check water parameters. This is often the easiest way to solve most problems or exclude a large number of potential issues.

However, if you’ve already done this and your water parameters are fine (and the tank is cycled), there’s likely another issue at hand.

Watch the gourami closely. Is it alone or are there other fish in the tank with it? Do you see any bullying behavior from other fish, such as chasing?

If the answer to these questions is yes and yes respectively, it’s likely that one of your tankmates is bullying the gourami.

Removing aggressive fish or placing the gourami in its own tank is an option to deal with aggression.

Overcrowding may be the issue as well. These fish do best in groups of 4 or more as they are fairly social. However, you never want to keep too many gouramis in a tank as they can be prone to fin-nipping if not given enough space.

Also consider anything else you have in the tank with your gouramis that may be taking up space, such as other fish, plants, or decorations. Perhaps you need to rearrange your tank.

If it’s not aggression that is causing the problem, then it may be something else in the tank that is causing stress.

Parasites are a possibility, but it’s less likely to be the reason for glass surfing as they would rather scratch (flash) on sharper objects such as gravel and decorations.

Once you’ve figured out the cause of the stress, you can address it.

For bullying, remove the fish that are tormenting your gouramis or move them to their own tank. If they are fine in a different tank, it may be time to rehome them if nothing else will work.

Gouramis do best in groups so be sure they have some buddies to play with if there is room. If there isn’t room, upgrade your tank, it’s important they have friends.

As for overcrowding, rearrange the tank or move some fish into their own tanks if you can do so safely.

If it’s something else that is causing stress (a new decoration, plant, substrate, etc), make sure to remove it or give the fish more time to adapt to it.

Hopefully, once the initial stressor is addressed, your gourami will stop fluttering around the tank.

Don’t expect them to be back to normal right away. They may take a few days. So just give them time.

And as always, If you notice fin rot or other symptoms similar to ich, consider checking out our medications guide!


Owner of AquariumGravel.com and also owner of actual Aquarium Gravel believe it or not! ;). Setting up beautiful aquarium sceneries and habitats since I was very young. Enjoy!