5 Signs that Your Guppies are Stressed

Novice guppy owners have a lot on their hands since growing guppies is both a science and an art. There are a lot of things to keep an eye out for, including signs of guppy stress, which is a thing.

Guppies are sensitive fish and will react negatively to factors that disturb their lifestyle. In the wild, guppies will simply move out of the area that causes them discomfort, an option that domesticated guppies lack. The enclosed environment of a fish tank forces guppies to stay and face the stressors.

This can influence guppies’ behavior and even affect their health in the long run.

Today’s article will dissect the main 5 signs of guppy stress and expose the causes and solutions to consider. That being said, here are compelling signs that your guppies experience stress:

1. Gasping for Air

This generally happens due to poor water quality, leading to inadequate oxygenation and water pollution. Your guppy will have a hard time breathing, which will cause it to open and close its mouth rapidly, looking like it’s gasping for air.

In most situations, you will see them doing this near the water’s surface. This is one of the first signs that something’s wrong with the water, and your guppy experiences significant discomfort. Don’t ignore this sign since it can quickly lead to death. You should verify the water parameters immediately, discover the case, and find a solution before it’s too late.

2. Poor or Complete Lack of Appetite

If you see your guppies changing their eating pattern, see if you can identify the problem. There are many causes for lack of appetite, including disease, pregnancy, and stress. It’s easy to distinguish pregnant guppies due to their inflated bellies and distinct pregnancy spot on the lower abdomen.

Pregnancy also comes with several other signs, including hiding when labor triggers, immobile swimming, and convulsions. If these signs are not present and your guppy shows no obvious disease symptom, stress may be the only logical explanation left.

You will now have to identify the cause and seek for immediate solutions.

3. Lethargic Behavior

Just like the lack of appetite, lethargy can have many causes, including fish illness. If you notice that your guppy is lethargic, check for other signs of disease, including rotted fins, body discoloration, erratic swimming, etc.

If you can’t find anything relevant, then your guppy might be stressed. In this case, they may appear lethargic or lacking the energy they once had. They may also look to hide behind plants and rocks, looking to distance themselves from the stressors.

4. Erratic Swimming

This is another compelling sign of stress, but it can also include factors like poor water oxygenation and various fish disorders. This behavior can appear suddenly or progress as the causes worsen, dictating immediate countermeasures.

You may see your guppy swimming irregularly, not using its fins normally, rubbing on rocks and plants on purpose, and even crashing into objects. This is due to lack of coordination which can come from different sources, including constant stress, altering the guppy’s behavior.

5. Laying Still Near The Substrate

Laying on the substrate or swimming near the tank’s bottom is another sign of guppy stress. This is generally a defensive behavior as the guppies are being bullied by larger fish and seek hiding. It’s also one of the signs of guppy labor, but you can quickly rule that out.

Your guppy may show additional signs of stress in many cases related to fish illness. In those cases, finding the cause fast is critical to prevent more drastic consequences for your guppy population.

Why Are My Guppies Stressed?

Now that you know your guppies are stressed, how can you identify the causes? After all, without knowing the triggers, you can’t figure out a reliable solution. Here are the most common triggers of guppy stress that you have to consider:

– Predatory Species

Guppies are generally peaceful and friendly fish and will get along with a variety of other species. Adding unfit tank mates to the equation comes with the problem, which may bully, attack, and even kill your guppies.

Species like a piranha, tiger barb, red tail shark, flowerhorn cichlid, and even the tiny dwarf pea puffer are all aggressive species that don’t get along with many fish.

Some of these species may even kill your guppies or, at the very least, will bully them around the tank. This will cause the guppies to experience high levels of stress, stop eating and try to hide between plants and near the substrate.

If this is the case, you need to carefully monitor your tank dynamics to make sure your guppies are safe. If you see signs of bullying or other species engaging in predatory tactics, I advise removing the guppies from the tank.

You shouldn’t mix guppies with aggressive and bigger fish species that could treat guppies as food.

– Unfit Water Conditions

This is one of the most dangerous triggers to consider. Unfit water conditions can mean a lot of things, including:

  • Poor oxygenation – This can result from many things, including overcrowding, overfeeding, resulting in food waste, or dead plants around the tank. Your fish will begin to experience significant discomfort as a result and even start dying shortly.
  • Increased ammonia levels – This is a deadly problem, often arising from overfeeding, dirty tanks, lack of water changes, and even dead fish decaying in the tank. Ammonia poisoning is common in these conditions, affecting all fish in the process. If your guppies show signs of ammonia poisoning, you need to act fast. Some of the most compelling signs include discolored or red-blood gills, body darkening, lack of appetite, inflamed fins, etc.
  • Unfit water temperature – As tropical fish, guppies prefer warmer waters. The ideal temperature varies between 75 °F and 82 °F. They can go outside these parameters in both directions but not much and not for long. Their immune system will drop if the water is too cold, making the guppies more prone to infections, parasites, and disease. If it’s too warm, the oxygen level will drop, and we’ve already discussed where that goes.

– Overcrowding or Too Small Tanks

This is one of the most common problems in the guppy population since everybody wants as many fish as possible. Overcrowding, however, can lead to a variety of problems, including increased aggression and territorial behavior.

The situation is that much more severe when you have mixed species, some smaller than others. Pairing guppies with larger fish in an overcrowded tank can spell disaster fast, causing your guppies to experience high stress and even fall sick and die.

Overcrowding is also one of the main causes of poor water oxygenation and water pollution, as fish waste tends to accumulate faster.

If the tank is too small, your guppies will also experience visible discomfort. The smallest tank should be no less than 10 gallons, which can easily hold 5 to 8 guppies, depending on their size.

If you have more guppies than that or larger, you will require a larger tank.

Holding multiple species will also raise another problem which is space requirement differences. Some species need more space than others. It’s up to you to figure out the middle ground and accommodate all fish species in the same tank.

– Overfeeding

It may sound weird, but overfeeding can also contribute to fish stress. That’s due to the aftermath, which involves food accumulating on the tank’s substrate. The food will begin to decay shortly, leading to ammonia build-up and hurting your fish in the process.

This is that much more of an issue in mixt tanks, where some fish eat more than others, leading to feeding disparities. If you own a guppy-only tank, remember to only feed your guppies once or twice per day. You should also only feed them what they can eat within a minute and try to get all the food remains out of the tank.

Another key point to remember is that different foods tend to pollute the water more, like egg yolk. Fortunately, egg yolk is also very high in fat, so you shouldn’t feed your adult guppies too much of it too often anyway.

– Fish Illness

Your guppies may experience a variety of conditions, some genetic, while others circumstantial. They can contract parasitic infections, fish TB, dropsy, bent spine syndrome, etc. These problems will affect their behavior, causing them to swim erratically, lack appetite, become lethargic, or swim in place.

Many of these conditions are contagious, which is why you need to address them rapidly. Treatment is available for some of the conditions, but not always. In most cases, you will most likely have to quarantine and even euthanize the sick fish to protect the rest of the population.

After establishing the cause of your guppies’ stressed behavior, you will now have to look for a solution. Continuous stress will affect your guppies’ immune system, rendering them vulnerable to parasites and disease.

Here’s what you can do to keep your guppies safe, happy, and healthy:

Identify the Cause

The first step is figuring out what’s stressing your fish. You can do that by assessing your guppies’ behavior and look for other signs of illness. If nothing stands out, check the water parameters and assess the dynamics in the fish population.

Maybe the fish displaying signs of stress is being bullied by others. Or maybe the water has low oxygen levels or increased ammonia, causing extensive discomfort. Whatever the cause, the faster you identify it, the sooner you will be able to figure out a solution.

Fixing the Problem

The solution always depends on the nature of the problem. I recommend starting with assessing your guppy’s general health. As I have already explained, many conditions will cause your guppies to experience stressed behavior, along with many other symptoms.

Check your guppy’s overall behavior, verify its colors, fins, tail, and eating patterns. If everything checks, you will need to check the cause of stress elsewhere. If there are signs of disease, you need to take appropriate measures.

I’ve already written other articles detailing guppy disorders and how to address them. If no treatment works, I’ve also written articles about euthanizing guppies humanely, with as little suffering as possible.

Adopt Reliable Preventive Measures

Once you’ve identified and addressed the causes of stress, you must now ensure they don’t return. In this sense, I recommend:

  • Controlling water parameters carefully, including temperature, oxygenation, ammonia levels, and bacterial accumulation
  • Change at least 50% of the water at least once per week, ensuring optimal oxygenation and a clean and healthy environment for your guppies
  • Assess the tank dynamics, trying to spot any aggressive fish behavior that may affect your guppies’ state of mind or physical health
  • Look for signs of bacterial or parasitic infections to address these problems in the early phases
  • Keep the guppy population under control to prevent overcrowding (I’ve written articles on this subject as well)
  • Look for signs of fish illness so you can quarantine the sick specimen before infecting the rest of the population, etc.

These measures should keep your guppies healthy, energetic, and happy in the long run.


Keeping guppies is relatively easy since guppies are easy to maintain and are calm and friendly fish. That being said, a lot of things can go wrong if you don’t pay attention.

The conclusion is simple – always keep the water parameters under control and check your guppies regularly to make sure everything checks.

Other than that, feel free to comment below in case you need further clarifications on the topic.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

Leave a Comment

Your email address will not be published. Required fields are marked *