Guppy Fish Laying on Bottom of Tank

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This is a question that comes up quite often, especially from beginners. The reasons behind guppy fish laying at the bottom of the tank can range from aquarium issues to pregnancy.

To help you identify the exact cause of your guppies laying at the bottom of the aquarium, I’m going to list all the possible causes and reasons why this usually happens.

So, why do guppy fish sit at the bottom of the tank and what can you do about it? Here are the most common reasons:

Pregnant Guppy Fish in Labor

One explanation for seeing a female guppy fish hanging out at the bottom of the aquarium is that she’s pregnant and in labor.

If you’re keeping both female and male guppies, chances are very high that they’ll reproduce and that the female will give birth to fry.

If the female guppy fish has an extended belly and seems to be seeking out peaceful or secluded corners of the aquarium, she’s preparing to give birth.

If you start seeing fry swimming around in the aquarium in a couple of hours, you can rest assured that the reason for her staying at the bottom of the aquarium was so she could release the fry peacefully.

Now that you’ve solved the issue of why is your guppy fish at the bottom of the aquarium, you’ll have another problem to worry about — what to do with all that guppy fry?

If you want to keep the fry, you should separate them from the adults, otherwise they will get eaten up by them.

What if the guppy that’s sitting at the bottom of the tank is not female, so it can’t be pregnant and in labor? If that’s the case, the issue is something else.

Stressed Guppy Fish

Stress can be another reason why your guppy fish may be hanging out at the bottom of the aquarium.

There are many things that can put stress on your fish including a noisy tank environment, too much handling (e.g. when fish is moved from one tank to the other), a poorly maintained tank.

Guppy fish can also become stressed if other fish are chasing them or hurting them. Female guppy fish can become stressed if male guppies are constantly pursuing them.

An overstocked aquarium can also cause stress because of heightened waste levels, toxins and lack of enough oxygen.

These are all problems that can stress out guppy fish and cause them to become more reclusive and stay at the bottom of the aquarium.

Poor Water Conditions

Bad water quality is one of the major stress factors and reasons why guppies may start behaving differently — they may become lethargic, they may lose their appetite and show symptoms of the disease.

When you set up a new aquarium — and this applies to any fish you’re trying to keep — you must first make sure that you properly cycle the tank.

Once that’s done, you can place your fish in one by one avoiding overstocking the tank. Guppy aquariums will also benefit from some plants that will provide coverage to fish and will help with water quality.

Additional equipment that you may need is a heater to keep the temperature stable and a filter system that will clean the water of debris and toxins. It’s also good to have an air pump that will keep the water well oxygenated.

But all these requirements are still not enough to ensure the best conditions for your guppies. Water changes performed regularly (weekly or biweekly) are also required.

Poor water conditions can hurt your guppy fish causing diseases, stress, which will eventually lead to the death of your fish.

Bad Tank Mates

Even if they may prefer water parameters in the same range, some fish just simply don’t get along with each other, this can lead to aggression, territorial behavior, fights, and injuries.

It’s also highly stressful on fish to be put into the same aquarium with fish they’re not compatible with. This can lead to behavioral issues like bullying, and weaker fish can end up dead.

When choosing tank mates for your guppy fish, make sure they’re compatible fish. Compatible tank mates for guppy fish include mollies, platies, swordtails, cory catfish, bristlenose plecos, etc.

Don’t keep guppy fish with large fish that may eat them or fin-nippers. Angelfish, cichlids, and Endler’s are not good options for guppy fish tank mates.

I also don’t recommend keeping fish that have different temperature requirements hoping that they’ll adapt. While some fish can adapt to live at temperatures outside their preferred range, most fish don’t.

Fish Disease

If your guppy fish is sick, you may find it laying at the bottom motionless or having difficulty swimming or breathing.

Many diseases can trigger this behavior or cause swimming issues including swim bladder disorder, dropsy, parasitic infections, bacterial infections, etc.

You should always try to look for other symptoms (e.g. spots or lesions on the body, ragged fins, loss of appetite, etc.) to help identify the type of disease that’s causing these issues.

If it’s a treatable disease, you should immediately use appropriate medication and perform water changes as required by the treatment.

You may need to transfer some of the sickly fish into a hospital tank for more personalized treatment and to prevent the spread of the disease to other fish.

Preventing diseases should always be your first line of defense. Always quarantine new fish, make your own cultured foods, perform regular water changes and set up all required equipment.

Ammonia Poisoning

Ammonia poisoning is another reason why you may find your guppy fish at the bottom of the aquarium. Ammonia poisoning can be deadly to your fish and ammonia levels should be monitored.

Ammonia poisoning can be sudden when there’s a huge ammonia spike in the aquarium (it can happen in newly cycled tanks) or it can happen slowly over a period of time if ammonia levels are not monitored and water changes are not regular.

Besides finding your guppy fish at the bottom of the aquarium, there are some other signs associated with ammonia stress or ammonia poisoning such as lethargy, loss of appetite, clamped fins, red streaks or bloody patches in advanced cases.

If noticed early, doing a major water change followed by frequent water changes can help lower the ammonia and prevent your fish from dying.

Why Guppy Swimming Strange at Bottom of the Tank?

If you notice your guppy swimming sideways or tipsy at the bottom of the tank, the organ that regulates their buoyancy, the swim bladder, may be damaged.

As a result, guppies may have trouble staying afloat and sink to the bottom of the tank. The most common cause is an enlarged abdomen or intestines caused by overeating or constipation.

Other times, the disease can be caused by an infection or parasite. Treatment depends on the root cause of the problem. If it’s caused by constipation, you should avoid feeding for a couple of days, then feed the cooked and skinned peas to ease constipation.

If the problem seems to be an infection or parasite, it should be treated with medication such as broad-spectrum antibiotics.

Why is my Guppy Fish Hiding?

There are a number of reasons why your guppy fish may seem like it’s hiding in the tank. The most common issue is an overstocked aquarium.

While a 10-gallon tank is recommended as the minimum tank size for guppy fish and anything smaller won’t do. Because these fish tend to breed very often, overstocking issues can easily appear.

If you add more fish and want to create a community aquarium, you’ll easily have an aquarium overstocking issue, and you’ll encounter problems with ammonia levels, oxygen levels, and diseases.

If an overstocked aquarium or water quality is not an issue in your case, your guppy may simply be pregnant and preparing to give birth.

Is my Guppy Sleeping at the Bottom?

Because guppy fish are diurnal animals, they do need to get some sleep during the night to recover and conserve energy.

If you notice that your guppy fish is floating above the gravel or other surface at the bottom of the tank during the night, you shouldn’t be alarmed, because your guppy is resting.

During this time, they may twitch a bit and flick their fins, but they’ll be generally in a resting state. If you have artificial lights in the aquarium, make sure to turn them off at night to allow your guppies to rest.

The situation is different, however, if you see this behavior happening during broad daylight. If this happens, then the problem may be one of the other issues I discussed in this article.


There are many reasons why guppy fish will be staying at the bottom of the aquarium including pregnancy, illness, overstocking issues, water quality problems, stress, etc.

If you notice this behavior in your guppies, you should first examine water conditions, perform a major water change if water parameters are off, and look for other symptoms to see if there’s also a disease involved.

Sometimes, you’ll notice guppies at the bottom simply because they’re resting at night or a female guppy may be preparing to spawn. Whatever the reason, it’s best to be prepared and know about these situations.

Updated: January 9, 2022

Questions & Answers

  1. Weve had our guppies for about 2 weeks. 1 is doing well, the other semmed a little off. Sometimes Id catch him swimimg near heater and wouldnt move at feeding time. Sometimes he would seem okay. We had 2 male guppies and 1 algea eater. He died over night. Found him at the bottom, belly up.

    1. avatar

      I think they died due to ammonia poisoning. If there is no sign of diseases, most likely poor water quality killed them. Probably your fish tank is not cycled yet and there are still ammonia spikes, which are very harmful for fish.

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