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Why Do Angelfish Stay at the Top of the Tank? (6 Causes)

Why Do Angelfish Stay at the Top of the Tank? (6 Causes)

This post is written to the author's best knowledge and is not intended to be used in place of veterinary advice. In addtion, this post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.

Getting angelfish for your aquarium should be a lot of fun. These pretty fish will be a great addition to many different types of tanks.

Some choose to keep angelfish in community tanks, but they can also be kept in their own tanks with just other angelfish. They’re amazing fish that are so fun to observe due to how gracefully they move through the water.

It’s also notable that there are many different color variations. You can purchase angelfish that will suit your sensibilities by looking at your local aquarium store.

If you recently bought some angelfish, then you’ll likely be worried if they start acting strange. Under normal circumstances, the fish will swim around the middle of the tank, but what does it mean if the fish stays at the top of the tank?

Going to the top of the tank isn’t unusual on its own, but staying there might be a little odd. Should you be concerned that something is wrong with the fish?

Keep reading to learn some of the reasons why angelfish might choose to stay at the top of the tank. This should give you a better idea of what is going on in your situation.

1 – There Might Not Be Enough Dissolved Oxygen in the Water

Oxygenating Fish Tank

The first thing to consider is whether the angelfish is simply trying to breathe. Does the angelfish seem to be gasping near the top of the fish tank?

If this is the case, then it’s very likely that it’s trying to get oxygen. You see, angelfish utilize dissolved oxygen in the water so that they can breathe.

When there isn’t enough dissolved oxygen present in the water, it makes it difficult for them to breathe. The angelfish could be moving to the top of the tank in an effort to get more oxygen.

Angelfish absorb oxygen through their gills from the water. The fish might be hoping to find a spot with a higher concentration of dissolved oxygen.

Since oxygen is a type of gas, it’s going to rise to the top. The top of the tank should be a spot where there will be more dissolved oxygen.

You might have an issue where the lower depths of your fish tank doesn’t contain enough dissolved oxygen. Thankfully, this is an issue that you can fix so that you don’t have to see your angelfish struggling to breathe.

Purchase an air pump or an air stone that you can add to the water. This will help to oxygenate the water so that the angelfish will be able to breathe easy.

Placing air stones in the fish tank will be a very easy solution. Do your best to use this method to keep around 8 ppm of dissolved oxygen in the aquarium.

2 – Significant Water Quality Issues

Angelfish in Poor Water Quality

Perhaps the water in the fish tank is too dirty for the angelfish? If you aren’t doing a good job of keeping the fish tank clean, then the fish could be gasping for air at the top due to how unclean things are.

Generally, this is only going to happen when your filter isn’t working properly. The filter should do a good job of keeping the fish tank clean.

If the filter stops working, then ammonia, nitrates, and nitrites will start to become an issue. Too much ammonia will make it impossible for your fish to breathe, and this is likely why the fish is trying to hang out near the top of the tank.

Many things can cause the fish tank water to get dirty. Too much fish waste in the water is a common reason why things will start to get dirty.

If the filter isn’t getting rid of the excess waste as normal, then you’re going to encounter issues. Rotting plants can also be a significant problem.

You should try to ensure that your filter is working properly to avoid situations like this. It’s also a good idea to buy a high-quality filter that you can rely on.

Another thing worth knowing is that changing the water out regularly helps. If you haven’t been changing the water out every so often, then the water can get way dirtier than it should.

Even when you’re using a filter, it’s a good idea to change out a bit of the water each week. Some people change out 15% of the water each week, but you might be able to change out a larger percentage of the water biweekly if that would work better for you.

3 – Improper Water Temperature

Thermometer in a Fish Tank

Not having the water at the right temperature will be very bad for your angelfish. You need to try to keep the angelfish tank warm enough for them.

Ideally, the tank should be kept between 76 degrees Fahrenheit and 84 degrees Fahrenheit. While it’s true that angelfish can survive in temperatures that are slightly cooler or hotter than this, you’ll want to keep the water in the right temperature range for the sake of the fish.

The angelfish will be much healthier if you ensure that the water temperature is correct. Angelfish that are made to live in cool water for too long might not live very long.

It’s also worth noting that angelfish don’t like sudden temperature fluctuations. They might start acting strangely if the temperature swings too far in one direction very fast.

To keep things such as this from happening, it’s highly recommended to get a heater for the tank. Even if you live in a warm region of the world, using a heater for the tank is better since it’ll keep the tank at a consistent temperature.

In the wild, angelfish deal with temperature fluctuations, but the fluctuations generally aren’t severe. They’re more gradual and it’s not so bad for the fish to deal with them.

You’ll want to get a heater that has a thermometer as part of the package. This will make it easy to see what the temperature of the water is at a glance.

Otherwise, you can buy a standalone thermometer to test the temperature of the water. If you keep an eye on things, then it should be easier to protect the fish.

4 – The pH Balance Matters Too

Man Holding PH Tests for Freshwater Aquarium

The pH balance of the water is also going to matter. Have you been remembering to check the pH balance regularly?

You need to keep the pH balance between 6.8 and 7.8 for angelfish. If the pH balance is outside of this range, then it won’t be good for the fish.

It can lead to various issues such as the ones described in the dirty water section. You should be testing the pH balance of the water weekly to ensure that things are where they need to be.

Testing the water is very simple because you just need to buy a pH balance testing kit. It doesn’t take long at all to determine where you’re at, and you’ll be able to fix things up in no time as well.

You can raise or lower the pH balance of the water using special chemicals. This is the easiest way to get things where they need to be for the angelfish.

5 – Aeration Problems

Tank with Angelfish

You should also consider whether aeration problems are causing your angelfish to stay at the top of the tank. Some people have a hard time differentiating aeration from oxygenation, but it’s actually pretty simple.

Aeration refers to how well the oxygen in the water is getting spread around the tank. You can have lots of oxygen in the tank, but it’ll still be a problem if it isn’t getting where it needs to go.

If the water isn’t flowing properly, then the dissolved oxygen might not be getting to the bottom of the tank. This causes the fish to go to the surface to try to get as much oxygenated water as they can.

Solving this problem is as simple as making sure that the aeration is being handled properly. Getting a stronger water pump that is capable of moving the water around will be able to get things back to normal.

You need a bit of water movement to ensure that the water is aerated. If there is no movement, then aeration is going to become a big problem.

Note that angelfish don’t like strong currents, though. If the current is too strong, it’ll make it tough for them to fish.

You should buy a powerful enough filter that will be able to aerate your tank, but you don’t want to go overboard. Having plants in the tank can help to dull the strength of the current, and that might help if you’re having issues.

6 – The Fish Might Simply Be Looking for Food

Angelfish Eating at Top of Tank

It could easily be the case that the fish is simply looking for food. Angelfish are hungry fish that will always act as if they want to eat.

If the fish is feeling hungry, then it might swim to the top of the tank to see if any food is present. The fish get used to the idea that the food comes down from above.

Your fish might be simply hoping that you’re going to feed it soon. If you feed your fish on a regular schedule, then you don’t need to worry about the fish doing this.

It should be safe to ignore the fish going to the top of the tank looking for food. This is assuming that you aren’t starving your fish by forgetting to feed them for several days in a row.

Fish can go a fairly long time without being fed, but you shouldn’t wait too long to feed them. An adult angelfish might be able to live a week without being fed, but it’s recommended to feed it twice daily if you want it to remain in good health.

When feeding an angelfish, you’re supposed to feed it as much as it can eat in two or three minutes. You don’t want to feed it more than that or else it could become constipated.

Constipation issues are very problematic because they usually cause swim bladder issues that make a fish lose control of its buoyancy. Just remember to feed your adult angelfish twice each day and everything should be just fine.

Angelfish eat special fish flakes that are meant for angelfish. They also eat shrimp pellets.

Many enthusiasts say that mixing things up will be good for the fish. So you can feed it flakes sometimes and then feed it shrimp pellets on some days to give it a different experience.

Final Thoughts

You’ve now learned about many reasons why angelfish might choose to swim near the top of the tank. Some of them aren’t concerning at all, but others will require your attention.

If the fish seems as if it’s just looking for food, then you should be safe to ignore it so long as you have been feeding it regularly. In fact, it would be very bad to make the mistake of feeding the fish too much.

Just be careful to determine whether there is anything wrong with the water. Sometimes the fish might swim at the top of the tank as a way to try to get oxygen.

If there isn’t enough dissolved oxygen in the water, then the fish might go to the surface to try to get what it can. Oxygen rises, and this means that the most dissolved oxygen is going to be at the top of the tank.

You can fix this issue by getting an air stone for the tank. This will help to ensure that enough dissolved oxygen is being generated in the aquarium.

It’s also wise to check on the aeration because the oxygen needs to get spread around the tank. Using a water pump to ensure that the water is getting moved around properly is essential.

Remember to keep the water temperature in the right range. If the temperature is too cold or too hot, then it can stress the fish and cause them to experience health issues.

The same thing can be said for the pH balance of the water. You want to check the pH balance regularly to ensure that it stays between 6.8 and 7.8.

Do all of this, and you should be able to solve any problems that the angelfish are experiencing. Remember to be a proactive fish tank owner and you’ll be able to enjoy your angelfish for a long time to come.