Why Do Fish Lay At The Bottom Of The Tank?

by Aquarium Scoop | Last Updated: October 28, 2022

There are several reasons your fish is lying at the bottom of your fish tank. It’s not always a cause for concern, but it could be a sign of illness. Some fish are bottom dwellers, so in some species, this is completely normal behavior.

In this guide you’ll learn:

• Why do fish lie at the bottom of the tank?
• Illness that can cause this behavior
• Fish that commonly dwell at the bottom of tanks

5 Reasons Why Fish Lay at the Bottom of the Tank

If you’ve noticed your fish hanging out at the bottom of the tank more often than usual, it could be a sign that something’s wrong.

Here are a few possible reasons why your fish might be lying on the bottom of the tank:

1. There’s Not Enough Oxygen in the Water

If the water in your tank isn’t well-aerated, it could cause your fish to experience respiratory distress. This can cause them to seek out lower tank levels where there’s more oxygen.

2. The Water Temperature Is Too Cold

Fish are cold-blooded creatures, so they’re susceptible to changes in water temperature. If the water in your tank is too cold, it can cause your fish to become sluggish and listless. Check the water temperature and ensure it’s within the ideal range for your fish species.

3. The Water Quality Is Poor

If the water in your tank is dirty or contains too much ammonia, it can make your fish sick. Poor water quality can also cause your fish to become stressed, leading to them lying on the bottom of the tank.

4. Your Fish Are Sick

If your fish is lying on the bottom of the tank and showing other signs of illness, such as lethargy, loss of appetite, or unusual behavior, they may be sick. Various diseases and parasites can cause fish to become ill, so consulting a veterinarian is usually the best decision.

5. Your Fish Are Spawning

If you have female fish full of eggs, they may lie on the bottom of the tank to release their eggs. After the eggs are released, the female fish will usually swim away and leave the eggs to be fertilized by the male fish.

Diseases That Can Cause Fish to Lay at the Bottom of the Tank

If you notice that your fish is lying at the bottom of the tank for extended periods or appears listless and uninterested in its surroundings, it could be sick.

Several diseases can cause fish to lay at the bottom of the tank, including Swim Bladder Disease, Dropsy, and Ick (also known as White Spot Disease). While these diseases can be severe and even fatal if left untreated, many effective treatments are available. If you think your fish may be sick, you should take them to a veterinarian as soon as possible for diagnosis and treatment.

Swim Bladder Disease

One disease that can cause fish to lay at the bottom of the tank is called Swim Bladder Disease. A fluid build-up causes this condition in the swim bladder, a small sac that helps fish stay buoyant. If the swim bladder becomes full of fluid, it can cause the fish to sink to the bottom of the tank. 

Symptoms of Swim Bladder Disease include: 

• Bloating 
• Difficulty swimming
• Listlessness

Dropsy

Dropsy is a condition that causes the fish’s scales to stand up and the belly to swell. This swelling is caused by fluid build-up inside the fish’s body. Dropsy is treated with antibiotics and sometimes requires hospitalization in severe cases.

Symptoms of Dropsy: 

• bloating 
• lethargy 
• loss of appetite 

If you notice your fish lying at the bottom of the tank, it’s crucial to take him to the vet immediately. These diseases can be deadly if left untreated, so don’t wait to get your fish the help he needs.

Types of Fish That Stay at the Bottom of a Fish Tank

If you find your fish hanging out at the bottom of the tank more often than not, there’s no need to worry. Many fish species are known to stay close to the bottom, and there are various reasons your fish may be doing this.

Some fish, like catfish, bottom-dwelling fish, and loaches, spend most of their time near the bottom of the tank because that’s where they feel most comfortable. 

Other fish, like corydoras and plecos, hang out at the bottom to look for food.

Angels and gouramis stay at the bottom to avoid being bullied by other fish. 

Whatever the reason, there’s no need to worry if your fish are spending more time at the bottom of the tank. They’re probably just fine if they’re eating and swimming normally.

5 Ways to Determine If Your Fish Is Sick

If your fish is lying at the bottom of the tank more than usual, it could signify illness.

Here are five ways to tell if your fish is sick:

1. Change in Behavior:

If your fish is usually active and swimming around but is now lethargic and lying at the bottom of the tank, this could be a sign of illness.

2. Change in Appearance:

• If your fish’s scales are lifting
• Cloudy eyes
• Frayed fins

3. Change in Appetite

If your fish has stopped eating or is eating less than usual, this could be a sign that something is wrong.

4. Change in Waste:

If your fish is producing more waste than usual or its excrement is abnormal in appearance, this could be another sign of illness.

5. Swimming Erratically:

If your fish is swimming in a jerky or erratic manner, this could also be a sign that it is not feeling well. If you notice any changes in your fish, you must take it to a vet or an experienced fish keeper for a diagnosis.

Conclusion

Many effective treatments are available for diseases that can cause fish to lie at the bottom of the tank, so don’t hesitate to get help if you think your fish may be sick. If you’re concerned about your fish or other aquatic life, Aquarium Scoop offers educational services to help you take care of them. We can teach you everything from the basics of aquarium maintenance to more advanced topics like diseases and treatments.