Why Is My Platy At The Bottom Of The Tank? (With 5 Solutions)

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When I saw that my platy fish was at the bottom of my tank, I panicked. I kept wondering what could have gone wrong and thought about all the possibilities. As I investigated the issue further, I realized that the fish actually signals that it is distressed.

Platy fish tend to stay at the bottom of the tank when they are stressed. That could be secondary to inappropriate water conditions or an underlying ailment, such as Ich or swim bladder disease. However, in some cases, platys lay at the bottom because they are pregnant and about to give birth.

As we move forward, I will share five steps to help you deal with platys that refuse to leave the bottom section. That includes the equipment that I use to measure my aquarium parameters, with pH, ammonia, and nitrates in particular.

Why Is My Platy Staying At The Bottom Of The Tank?

If your platy is lying still at the bottom, you must consider the possibility that the platy prefers the bottom. Don’t be so quick to assume that something is wrong. Platys tend to swim all over the tank. However, fish don’t have the same personalities. 

More importantly, you can never predict the type of platy you will get in the tank. If your platy is perfectly happy at the bottom, you don’t have to overthink the issue. The fish simply prefers the bottom. That being said, if this behavior is new, you are right to show concern. 

Some factors that may cause a platyfish to stay at the bottom of the tank include:

1. Your Platy Is Pregnant

Platys are almost always pregnant. You don’t have to encourage them to breed. This is a problem for people with small tanks that do not want more fish. Pregnant platys spend a lot of time in hiding. They do this because they want to find a secure place to give birth. 

A pregnant fish may stay at the bottom because it has identified the substrate as a suitable birthing location.[1] It is also worth noting that pregnant platys do not eat as much. Some female platys will stop eating altogether as their due date approaches. 

Because they do not have as much energy to waste, they may choose to spend their days at the bottom, resting. Pregnant platys are not that difficult to spot. They have large bellies with a dark gravid spot. If you’re interested, here is an excellent video that will help you identify a pregnant platy fish:

2. The Platy Is Carrying A Disease

Platys are susceptible to various illnesses. One of the most common is Ich. It causes white spots to cover their bodies. It also causes an element of discomfort that compels the platys to rub their bodies against any hard surface they can find. Some platys spend a lot of time at the bottom because they want to rub their bodies against the substrate.

Other illnesses like fish Tuberculosis, Dropsy, and Velvet disease will cause lethargy, listlessness, and inactivity in the platys. The fish are so exhausted that they don’t have the energy to swim. As a result, they will sink to the bottom where they will stay because they need the rest.

Some diseases can create a barrier that compromises a platy’s ability to swim. For instance, swim bladder disease affects the organ that platys use to maintain their balance in the water. For that reason, some platys that contract swim bladder disease cannot swim away from the substrate no matter how hard they try.

Scoliosis is another problematic illness that bends the fish’s spine, making swimming so difficult that some platys will choose to lie at the bottom because it is the less strenuous option.

3. Bad Water Conditions

The wrong water conditions can have a multitude of consequences. First of all, they will induce stress in the platys. Secondly, the wrong conditions will lower the immunity of the fish, making them more susceptible to illnesses. 

If your tank is dirty, ammonia will become an additional concern. High concentrations will burn the gills of the platys, resulting in labored breathing, which tends to force fish to the bottom. If the ammonia levels in your tank are appropriate, test for other toxins. 

I usually test for chlorine, chloramine, copper, lead, and any other dangerous element that aquarists accidentally introduce to their aquariums via new water, new plants, new decorations, fertilizers, fish medicine, and the like.

If you are convinced that your aquarium is free of toxins, check the temperature. Because the bottom section of a tank is often cooler than the upper sections (warm water rises), platys living in a tank that is too hot will run to the bottom.

Even if they can tolerate the heat in the upper sections of the tank, you cannot ignore the fact that cold water holds more oxygen than hot water. A spike in the temperature will produce an oxygen deficiency, forcing the platys to flee to the bottom, where the water is cooler and more oxygen-rich.[2]

4. Your Platy Is Stressed

Inactivity is one of the most common symptoms of stress in fish. It is often accompanied by timidity and a loss of appetite. Stress has various causes in platys, including poor water conditions, ammonia poisoning, overfeeding, underfeeding, diseases, and even loneliness.

Platys are not shoaling fish. They don’t have to live in groups.[3] However, platys are very social. If you force them to live alone, some of them will become so unhappy that the stress will force them to lie at the bottom of the tank.

5. The Fish Is Actually Dead

A dead fish will sink to the bottom of the tank. It will only rise once it starts decomposing. If your platy fish has stopped moving altogether, you must consider the possibility that it is dead. This happens all the time. Fish can die quite suddenly for many reasons, including poor water conditions, disease, and stress. If you think your platys are dead, use a net to scoop them out of the tank. 

Living platys will struggle against this transition. Dead platys won’t respond. If you don’t want to take the fish out of the water, lift it to the surface where you can see its gills. If the gills have stopped moving, the fish has stopped breathing and is most likely dead. You can also look at the eyes, which are usually sunken with cloudy pupils.

What Should I Do If My Platy Is Laying At The Bottom?

If your platys are dead, remove them from the tank before they ruin the water. If they are alive but happy at the bottom, leave them alone. But if they are alive and clearly distressed, these are just a few of the steps you can take to help them:

1. Setting The Right Water Conditions

Start by improving the conditions in the tank. I suggest giving the platys a temperature of 70 to 80 degrees F, a pH of 7 to 8, GH of 10-28 DGH, and a KH of 3-5 DKH.[4] They also need at least 10 gallons of water. Though, many aquarists argue that you shouldn’t keep them in anything smaller than 20 gallons. At the end of the day, the bigger the tank, the better for your platys.

Here is the equipment that I use in my tank to measure these parameters:

  • The API FRESHWATER MASTER TEST KIT (link to Amazon) helps me measure the pH, ammonia, nitrates, and nitrites. I love this bundle because it is highly accurate and lasts for hundreds of measures. Within five minutes, it tells me if something went wrong.
  • I use the Seachem Prime Conditioner (link to Amazon) when toxins like ammonia or nitrates go beyond the desired range (which is 0 ppm). If you are new to this topic, here is an article where I discussed how much water conditioner you should put in your fish tank.

While some people have successfully maintained aquariums without heaters, you should install a heater if you have the means because it allows you to maintain a stable temperature. 

I personally got the Cobalt Aquatics Neo-Therm Pro Aquarium Heater (link to Amazon), which I also reviewed here. That is the only device that actually keeps my temperature stable. It is worth mentioning the frequent fluctuations will stress your platy and possibly force it to stay at the bottom of the tank.

If your region is prone to very hot summers, you have the option of switching the heater off on hot days. You can also dim or switch the lights off when the temperature is too high. Some people have gone so far as to add ice cubes to their tanks. You can do this as a last resort if your aquarium is too hot.

2. Cycling Your Tank Properly

Make sure the tank is fully cycled. This takes several weeks. Cycling is essential because it introduces beneficial bacteria that can process the ammonia in the tank, converting it into nitrites and nitrates, which are less toxic. If your tank isn’t properly cycled, the ammonia levels will keep spiking until they kill your platys.

3. Adding A Few Plants

I recommend adding some plants to the tank. An aquarium with foliage will put your platys at ease, alleviating their stress. This is because plants provide hiding places. The platys can use them to escape the large and aggressive fish in their environment. You can complement the plants with decorative items like caves and driftwood. They also provide hiding places.

4. Growing Platys In Groups

Even though they can live alone, you should keep your plays in groups of five or more. This makes them feel safe. They are also happiest in groups. I also suggest pairing them with peaceful fish like mollies, tetras, and swordtails.[5] 

Please avoid larger creatures like Oscars and African Cichlids that might be tempted to eat them. Even if the larger fish don’t eat the platys, they will make the platys’ lives difficult. Their presence will induce stress in the platys.

5. Dealing With Diseases

If you suspect that your platy is sick, please consult an aquatic veterinarian. Experts will help you identify the underlying cause of your platy’s condition. They will also adjust the proper treatment for your particular situation.

But you can start treating sick platys on your own by cleaning their tanks. Perform a 50 percent water change to reduce the concentration of toxins. Once the tank is clean, you should perform 20 percent water changes every week. If your platys are too weak to survive a significant water change, you can always use conditioners to neutralize the toxins in the water.

Take a more proactive approach to their hygiene. Every platyfish tank requires a filter. But you can’t trust the filter to remove all the leftovers and pollutants. You have to remove some of the debris yourself. You are also expected to vacuum the substrate.

If you can maintain a clean, toxin-free tank with the correct parameters, your fish’s immunity will improve, and that will enhance the rate of their recovery. Though, some illnesses require specific treatments. For instance, you can fight Ich with Seachem Paraguard.[6]

On the other hand, swim bladder disease caused by constipation requires a diet consisting of peeled and cooked peas. Bacterial illnesses like fin rot require antibiotic treatments like Maracyn and Tetracycline. If you don’t understand your fish’s disease, talk to a vet. They will diagnose the symptoms before recommending a suitable treatment.

Do Platys Sleep At The Bottom Of The Tank?

Some platys will sink to the bottom when they sleep. But others will hover in the water or float to the surface once you turn the lights off. That usually happens when the bottom section is already occupied with plants and decorations.

If your platy merely hovers in place and returns to its normal behavior after inducing stimuli, it was probably sleeping. But if your fish stays at the bottom the entire day, you should suspect that something else causes this behavior.

If you found this article helpful, these may also interest you:


Platys that stay at the bottom of the tank are usually stressed. The first step would be checking the water parameters, including the ammonia, nitrite, and nitrates levels. You should also check the hardness and pH. If the platy is healthy otherwise, it is most likely suffering from stress.

The second thing to consider is the tank temperature. If the fish stays at the bottom of the tank, it might mean that it isn’t getting enough oxygen. The fish could also be stressed by other aquarium inhabitants or disturbances from above.


  1. https://answerstoall.com/popular/why-is-my-platy-laying-on-the-bottom-of-the-tank/
  2. https://www.cuteness.com/article/causes-fish-lie-bottoms-aquariums
  3. https://www.aquariumcoop.com/blogs/aquarium/platy-care-guide
  4. https://modestfish.com/platy-fish/
  5. https://fishcareguide.com/platy-fish-guide/
  6. https://www.aquariumnexus.com/platy-fish-diseases-parasites-remedies/