Fish get stressed by a variety of reasons and there are definite symptoms by which you can tell if they are stressed or not. Every fish keepers must under all circumstances avoid actions and setup, which can stress out your fish. If not taken care of, stress can kill fish because they are very delicate. Normally any sudden change in surrounding environment such as water quality, lighting conditions, other tank mates, sudden change in water temperature, etc. will quickly stress your fish.

When fish get stressed they have a tendency to move away from conditions that are causing the stress. But since a fish tank is a closed environment, it is impossible for fish to move way and surrender themselves to the troublesome conditions. Fish start showing visible symptoms when they are under stress and as an owner of the tank it’s your duty to observe these signs and act immediately.

Here are some ways to find out if your fish is stressed or not.

Just like humans and other animals fish show visible signs of stress on their body and in their behavior in the fish tank. To identify a normal fish from a stressed one you must have a habit of first identifying what a normal fish movement and living is, then only you can identify what a stressed fish looks like.

There are various ways by which fish will tell you that he’s stressed.

The very first visible symptom, if fish is stressed is to look for abnormal swimming pattern. This may include rubbing body against glass surfaces from inside, rubbing body against decorative items or swimming back and forth.

All these visible signs indicate some sort of stress in fish and if not treated can lead to serious diseases.

Other visible signs of stress include locking fins to sides, some sort of spots on body that are not part of original design and ich. That is why identifying stress and quickly eliminating it’s cause is important for fish health. Many diseases can lead to death as well.

Some fish species when stressed show visible sign of change in body color. Many times some fish turn pale in color than normal when they are stressed.

Some visible signs of stress in fish can be as follows.

  1. Sluggish fish
  2. Fish not eating food because of reduced appetite
  3. Constantly hiding behind decorations or plants.
  4. Too violent movement in the tank
  5. Attacking other fish (Ream More)
  6. Sitting quietly in the corner of the tank (Read more)
  7. Gasping for air at the top surface of the tank (Read more)
  8. Fish rubbing body against glass
  9. Fish turning pale in color
  10. Fish rubbing body against decorating items
  11. Fins getting deteriorated
  12. Fist trying to jump out of tank (Read more)

Reasons that can cause stress in fish

Sudden changes in surrounding environment

The very common reason for fish getting stressed is the sudden changes made in the environment in which they live. This includes changes in pH levels due to large water changes, changes in water temperatures due to faulty heater or water changes, adding medications in the main tank etc. Let’s have a look at these closer one by one.

1) When there is a large water change (about 50%), it is necessary that all the chemical factors are taken care of. Fish are extremely sensitive to pH factors because pH decides alkalinity of water and when that changes fish are bound to suffer. When you want to do a water change make sure the new water that is being added is safe from all aspects such as pH, de-chlorinated and follows all the safe levels of other invisible gases such as ammonia, nitrites and nitrates.

2) A large water change will also change the temperature of water and this is another deciding factor for avoiding stress in fish tank. This factor plays an important role when you have a tropical fish tank where maintaining water temperature within a range is crucial for survival of fish.

Another reason for change in water temperature is when you have a faulty water heater. If heater stops working for a long time then changes in water temperature will be visible if you have a fish tank thermometer installed.

3) If you have a sick fish then never treat home in the main tank by adding medications directly. Always have a quarantine tank set up and move the sick fish there and add medications in the hospital tank. Any kind of meditation can affect oxygen levels in a fish tank causing fish to stressed out. This can be visibly identified f your fish is gasping for air at the top surface of the tank.

Stress because of other dominant fish

When you pick tank mates it is absolutely necessary that you check with their “compatibility” in the tank. This point is extremely important because if not taken care of you’ll frequently see deadly fights in your tank even causing death.

Some species are naturally dominant than others like to create their own space and territory in the tank. When they see other unwanted fish occupying their territory they tend to attack. Sometimes these attacks can cause physical injuries leading to serious infections if not treated. It is also possible that during such fish’s fins get blocked in decorations ad plants and tear off. In such cases it is always better to avoid fights by checking compatibility of species to start with. If this bullying becomes too much some fish will even jump out of fish tank to save their life.

When fish get bullied they go in stress and you’ll see visible signs of these in their behavior. To avoid attacks they will hide behind decoration or plants and even sit silently in the corner of the tank. Since a fish tank has a confined area, fish can’t go away from the boundaries and are left with nothing but bear a constant low level stress. If not treated, this can lead to serious diseases.

The only way to solve this issue is to remove dominant species from the tank and put the ones that can go well with other tank mates.

Stress because of medications added in the tank

Never add medications in the tank directly if you have a sick fish in the tank then. This could be done only if all your fish are sick, but if just one fish has a disease then it’s better to move him out into a quarantine facility and treat him there.

Depending upon the severity of the disease medications added to the tank will tend to decrease oxygen levels in the tank causing fish to gasp for air at the top of the tank. Reduced oxygen levels can cause stress in fish and you’ll see them breathing heavily.

To avoid this situation it’s best to test water regularly for all types of safe chemical levels and maintain water chemistry properly. At any time prevention is always better than cure and this applies to fish as well.

Too much human movement around the tank can cause stress

This is one of those reasons which is not really taken care of. Fish that are in the pet store suffer a lot from this problem. In a pet store there is constant human movement around the tank and fish can get stress just by human movement around the tank. Sometimes fish tank gets vibrations of the floor because of the human movement and this causes the tank water to vibrate slightly as well. To avoid this, the tank must be secured properly with good shock absorbent base.

When you buy fish from a pet store it is most likely possible that they are under stress because of this reason and that is why first they must be introduced into a quarantine tank for a minimum of 15 days to maximum of 30 days. In this hospital tank you can observe for any visible symptoms of stress and if found safe can transfer to the main tank. Read this article to learn more about this.

If you have kids at home, then many times they have a habit of tapping on the fish tank glass just for fun. Even such common behavior can cause stress in fish because this causes water to vibrate inside the tank. It is necessary to teach your kids about having respect for these lovely species and act accordingly.

In short any action that cause the fish tank and water to vibrate even slightly. While setting up your tank you can have it on a secured stand with good shock absorbent material and facility. If you have an air pump on the stand then see to it that it is not touching the glass of the fish tank from outside because it has moving parts inside of it that can cause vibrations in the tank water.

Avoid overcrowding of fish

Overcrowding can be a serious issue for fish because they will be competing for the same amount of oxygen present in the tank. If you add more fish in the same space then they will obviously produce more solid waste that gets settled at the bottom gravel and start contaminating the tank water.

This can produce an overload on the filtration system as well causing poor performance and contaminated water returning back. More fish i your tank also means that you’ll need frequent cleaning cycles making it difficult to maintain water chemistry intact. All this can greatly stress your fish and lead to diseases.

Adding fish to a non-cycled tank

Fish may experience stress if you add them to a non-cycled tank. The nitrogen cycle is an integral part of a healthy fish tank. The reason is in a non-cycled tank the ammonia, nitrite ad nitrate levels are not yet neutralized to safe levels and this obviously is going to cause trouble. Ammonia and other gases are highly toxic for fish and can cause great amount of stress and even diseases.

The best way is to cycle your tank and keep testing water using a kit. Only add fish in your tank when you see that all the gas levels are in safe zone.

How To Tell If Your Fish Is Stressed?