Clown loaches are well-known for doing funny things in fish tanks. These fish are full of life and certainly can be entertaining to observe.
What if the clown loaches start doing very unusual things, though? For example, you might notice that your clown loach is swimming up and down the glass.
You’re likely worried about this type of behavior. If it seems unusual for your clown loach, then it could mean that something is up.
Read on to learn why a clown loach might start swimming up and down the glass. This will ensure that you understand what’s going on so that you can potentially help the clown loach.
Most Refer to This as Glass Surfing
Most refer to this situation as “glass surfing.” This is a simple term that refers to fish swimming up and down the glass in a fish tank.
Many types of fish have been known to do this. Guppies, gouramis, betta fish, and other types of fish might exhibit this behavior for certain reasons.
Clown loaches are no exception. You might be observing your fish one day and will notice that it’s swimming up and down the glass.
If you’re someone who cares a lot about the fish, then you might be worried about whether this is a negative sign or not. Could it be that the fish isn’t happy in the fish tank?
1 – Loneliness

Did you know that clown loaches are supposed to be kept in small groups? There have been situations where people didn’t know this and chose to buy one clown loach as a pet fish.
Putting one clown loach in your fish tank is going to cause it to be lonely. These fish don’t do well when kept in isolation.
Even if there are other fish in the tank from other species, it’s not going to be a good situation. The fish swimming up and down the tank is likely a sign that it wants to get out and find more of its kind.
You should buy the fish some friends, assuming that you have enough room in your fish tank. These fish can get pretty big, and that means that the minimum tank size that you’ll need will be a 75-gallon one.
2 – Stress
Most types of fish will start glass surfing when they’re experiencing stress. It’s a sign that they aren’t happy in the fish tank.
This can be true of clown loaches as well. Seeing the loaches swimming up and down against the glass could be a sign that something is off.
They might be stressed for one reason or another. Since there are so many things that can stress fish, it isn’t always going to be easy to know what’s wrong.
Fish can get stressed when they aren’t being fed the right foods. Clown loaches will get very stressed if you don’t have enough hiding spots in the fish tank for them.
See if the fish are being stressed by something in the tank. If you can solve this issue, then the fish might stop glass surfing.
3 – Water Condition Issues

Water condition issues can make fish want to escape the aquarium. Is your water dirty?
You might have made some mistakes that make the fish feel as if they need to leave to find safer waters. No fish is going to want to live in dirty water.
Remember that you need to keep an eye on the pH balance of the fish tank. Clown loaches can tolerate a wide range of different pH conditions, but they still have a range that they find acceptable.
Aside from the pH balance, you also need to do regular water changes. If you’re not doing weekly water changes, then your clown loaches could easily become stressed.
Take the glass surfing as a sign that you need to check the water parameters. If things are off or if the water is too dirty, then you might need to make some changes.
4 – Not Enough Room
Clown loaches hate being put in cramped spaces. Trying to keep these fish in a tank that is too small for them won’t end well.
It wouldn’t be unusual at all to see fish glass surfing when they’re put in an overcrowded tank. The aquarium might not be large enough or there might be too many fish in the same tank.
Try to keep your fish in an aquarium that is the right size for them. If you’re going to include clown loaches in a community tank, then try not to cram too many fish in one tank.
5 – It Could Also Be Normal

Sometimes fish swimming up and down the glass will be normal. Clown loaches commonly swim in circles around the glass, but that’s a little bit different.
These fish like to play “follow the leader” when they’re in small groups. The fish will follow the lead fish and just do circles around the tank.
If the fish is swimming up and down the glass just a little bit, then it might be safe to ignore it. However, if this is happening a lot, it could be a sign that the fish is distressed.
It’s likely best to check things out and see if the fish has a reason to be upset with the tank. This will allow you to solve problems to try to make the fish happier.
Final Thoughts
There’s a chance that your clown loaches swimming up and down the glass will be an indication that something is wrong. Commonly, this behavior is referred to as glass surfing.
Fish do this when they’re unhappy with their living situation in some way. It could be that there are issues with the water parameters that are making the fish want to escape.
Other sources of stress can also cause clown loaches to act this way. It’d be wise to test the water and to try to pay attention to see what else might be going wrong in the tank.
It could be as simple as the fish not being happy about not having enough hiding spaces in the tank. Or it might be related to the fish tank being too small or overcrowded.
Fish that are too lonely due to being kept in isolation will often start glass surfing. They just want to get out and go find more of their kind due to extreme loneliness.
You must try to solve this problem so that your fish can stay happy and healthy. There’s a chance that this behavior won’t be an indication of problems in the tank, but you’re still going to want to check.
Jeff has always enjoyed having pets, but as a child, he was drawn to his family’s fish tank. Being able to maintain a small ecosystem and observe the behaviors and interactions in the underwater world peaked his interest early on and has kept him hooked until this day. On Avid Aquarist, Jeff shares everything he’s learned about helping aquatic life survive and thrive in a home aquarium.