7 Reasons Why Swordtail Fish Hide

Why do swordtail fish hide?

Swordtails fish are small freshwater fish because they could only reach 7 inches in size, and they are very active and lively, that’s why many people keep them. They sometimes exhibit some behaviors, which could either be funny or worrisome, and you might begin to wonder what the problem is. In this article, we will discuss the reasons they sometimes hide and how to prevent them from doing that.

Why do Swordtail Fish hide? They will hide when they are stressed, or simply because the water parameter is not suitable for them.

Swordtails have many characters which are why they are very entertaining to keep, and one of them is hiding.

There are many reasons why they do this, and we will discuss all of them and their solutions in this article, so you have to read carefully to understand all of them, which might help you to solve your fish problems.

Why Is My Swordtail Fish Hiding?

If you notice that your fish is hiding in the tank, some of the possible reasons for this behavior are:

1. Your fish is shy: Although you might be surprised at this, swordtails do get shy sometimes due to various reasons.

They are normally shy when introduced into a new tank/environment, so, if your fish is new to that tank, then, It is the reason, and you have nothing to worry about, because it is just shy, and that is their normal behavior when they are newly introduced to an environment, and they will get used to it as time goes.

Another reason they might become shy and start hiding is, if there is any other fish there, I mean, bigger fish, and it is intimidating them, so they will become shy and hide in any hiding places they could see in the tank.

2. Poor water quality: Sometimes if your swordtails are hiding, then, there must be something wrong.

Poor Water quality is one of the reasons they hide and become less active, and even if they come out, their level of activity will reduce, and they become very dull.

You might even notice that they are jumping and trying to escape from the tank, and they will succeed if the tank is not well covered with a tank lid.

This is very common for all swordtails when they are not very comfortable in their tank because of poor water quality or wrong water parameters.

Their ideal water parameters are –

Water Condition Hard, Alkaline water(12-30dGH)

Water Temperature 65-80°F.

pH up to 8.2.

So, if the water condition is not as they want it, or like it, they might become less active, try to escape, or even hide.

3. Another reason why your fish might hide is that it may be hiding from bullies in the tank.

Swordtails are very peaceful fish, but they sometimes bully each other, and might even kill each other as a result.

The males are guilty of this. When there are more males in a tank than the females, the males will start a war of supremacy to know who becomes the alpha male and gets the majority of the females.

When the supremacy is established by one male, the other males will have no option but to go into hiding, or risk being chased about and nipped at by the alpha male.

Again, the females could be bullied too by the males fighting over them, and harassing them for them to mate.

This harassment could lead to stress, and might even kill the females, so, to protect themselves, they will go into hiding too.

So, If your swordtails are hiding, then, there might be a bully in your tank.

4. Your fish may be sick: Swordtails are prone to many diseases and parasites, which sometimes stay at the surface of the water in many tanks.

All fish, including swordtails, are easily affected by bacteria, diseases, viruses, and fungi infections.

Tapeworms, nematodes, trematodes, lice, and leeches are very likely parasites to infect any fish if proper care is not taken.

In aquariums, the organisms occur at very low levels and may affect a small number of swordtails. Some of the things that characterize infected fish are sterility, slow growth, stunted population, and high mortality rate.

Fortunately, parasites and fish diseases are unlikely to reach epidemic levels, and they are rarely the cause of most deaths in aquariums.

A swordtail fish suffering from parasites or diseases dies slowly and you might lose several fish in a day.

But if the fish are in starvation, poor condition, injured, overcrowded, stressed, mixed with the wild fish or the levels of oxygen are low and temperatures are high, the parasites and diseases will become a serious threat.

Mostly, the affected fish show visible discoloration, sores, bleeding, popeyes, lumps, white or black spots, and abnormal growth on the fins and head.

The sick fish will act and look abnormal and may hide most of the time.

So, if your fish is showing some of the above signs and goes into hiding, then it is probably sick.

5. Your fish may be suffering from stress:

Stress on its own is like a disease, and no fish like to be stressed, because it could even lead to their death if they are stressed enough.

Some factors that could cause stress for fish and other aquarium animals are wrong tank mates, bullying, uncycled tank, and harmful chemicals in the water such as ammonia, nitrites nitrates, chlorine, etc.

All these factors could be agents of stress, and to protect themselves, the fish will have to go into hiding or lay at the bottom of the tank very tired and helpless.

6. Sometimes swordtails go into hiding because they are pregnant:

Though this could come in two forms, it’s either the pregnant fish is chasing others into hiding, because, they normally become very aggressive when they are pregnant and will attack any fish that cows close to them, or the pregnant fish itself is the one hiding, to have her babies and protect them.

Note – Swordtails do eat their offspring, so, try to relocate every adult fish in the tank, to give the young fish a chance to live.

7. Like I explained above, these are shy fish, and they don’t like being in a place where there is a lot of traffic or where their water is often being tampered with.

For instance, keeping them at a location where dangerous animals like cats or dogs walkabout will only scare them into hiding.

Also, they will have to hide if people walk around, or if noises are being made, it will startle them, and they will have to retreat into their various caves, behind plants, and even on substrates, etc.

Now, that you have seen the reasons why your swordtails might be hiding, let’s look at the solutions to all these problems.

How To Stop Swordtail Fish From Hiding

1. Always check your water parameters, and try to check the chemicals in their water, and once you notice any rise in any of them, such as ammonia, nitrate, etc, you might do a 50-70% change of water, depending on the level of the chemicals.

To do this, you need to have water testing kits in your house. So buy them for your own good.

2. Immediately you notice any sign of sickness in your fish, act fast and get a Veterinarian doctor to look into it and give the possible medications or medical advice.

We don’t give medical advice here, so contact a Vet.

3. Bullies should be identified and removed to another tank, all alone, and should be reintroduced back to the former tank, so that they will become less aggressive and dominating.

4. Introduce more females in the tank than males.

The recommended ratio is 2-3 females to 1 male.

Once this is done, they won’t have to fight, nor bother the females again, as there are many females to mate with.

So, this will reduce the level of aggression and stress in the tank.

5. Before introducing them in a new tank, make sure the tank is fully cycled, check the chemical level and know if it is safe to keep them there or not


These are the reasons why your swordtail. fish is hiding, and the possible solutions.

I hope this article is helpful to you.