Do Fish Lose Color When Stressed?

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Many fish keepers have a preference for stand-out colours in their fish and so, they are easily bothered when there is a colour change. The truth is fish might not always maintain their vibrant colours or magnificent looks as something could cause a change in their colours.

In this article, therefore, we will be considering whether stress is one of those factors that could cause your fish to lose colour.

Do Fish Lose Color When Stressed?

Diet is one of the biggest contributors to a fish’s colour and so, most times, when your fish start losing colour, you might want to think in that direction. However, this is not always the case as stress is another factor that should be paid attention to.

Stress can readily influence the colour of your fish and could be responsible for your fish losing its colour. It might be quite difficult pinpointing what exactly could be the reason why your fish is stressed. There are different reasons why your fish could be stressed.

The most common reason why your fish could be stressed is its living conditions. This means that if there is an issue with the aquarium size, water parameters, tankmates, and appropriate measures, this could result in stress for your fish and could eventually cause a change in colour.

There are some needs of fish that fish keepers do not pay attention to that could lead to stress in fish sometimes. This could be not providing shoaling fish with good tank mates, not enough lighting or not being able to retreat for timid fish. This could sometimes lead to a distressed fish.

So, not providing the correct care for the fish could cause stress for your fish and that can eventually lead to your fish losing colour. This means that it is very possible for your fish to lose colour when stressed.

How To Tell When A Fish is Stressed?

Fish sometimes exhibit a range of behaviours that could be an indication of their stress level. You would have to be very observant with your fish to know when they start exhibiting such. So, we will be considering some signs in stressed fish which can ultimately cause a colour change.

– Glass Surfing

Unlike when they are in their wild habitats when fish are stressed or unhappy, they don’t have anywhere to go. They can’t just leave as they want to when the water conditions are poor or when another fish is giving them some form of distress.

When some fish are stressed, they could exhibit what is called glass surfing. In this scenario, you just see the fish swimming up and down the sides of the tank glass for long periods. This is them saying they want to leave and they are stressed. If this is not dealt with in time, it could cause them to lose their vibrant colours.

– Flitting Around The Tank

Startled fish can get injured by running into aquarium decorations or glass. Some fish might even want to jump out when they see something that startles them. It is therefore important that you don’t put your fish tank in a place where there is a lot of human activity. This might get your fish startled

You also have to ensure that you find ideal companions for different fish species. This will help ensure that the fish do not stress each other out or cause any harm to each other. Any of these things could cause stress in your fish and could be the reason why your fish has lost its colour.

– Excessive Hiding

It is quite normal for fish to want to withdraw into spaces where they feel safe. While some fishes could hide more than others, others can decide to hide at certain periods of the day. However, if you notice that your fish has been excessively hiding when it would not, then something could be wrong.

A stressed fish might resort to hiding when it feels threatened. This might be because of an aggressive tank mate or maybe because they share a tank with a dominant specie. If you see a fish chasing them when they come out of hiding, that could be the reason why your fish is hiding.

Sometimes, fish could also hide when they are injured. This could also be down to an aggressive tank mate or a sharp object or decoration in the fish tank. When you notice all these signs in a fish that wouldn’t exhibit such signs, then it is highly probable that your fish is stressed.

– Changes in Appearance

Extreme stress can cause a terrible effect on your fish. Some fishes that are bullied or harassed can have notable changes in appearances. Even though fish might not have a lot of weight to lose, when they are overly stressed, they could be seen as wasting away.

This scenario can be quite awful and pitiful. If you have ever seen it happen to a fish before, you might never forget it. This could also cause the premature death of the fish. The fish could even lose their lustre when they are stressed.

A very vibrant and colourful fish could become dull. In betta fish, you could notice their face and jaws becoming light greyish when they are stressed. So, some fish could exhibit changes in appearance when they are stressed.

– Fin Deterioration

In this instance, a fish fin begins to deteriorate. This can eventually spread to the entire body of the fish. It is a bacterial infection and it could get pretty messy for the fish as it could increase the stress levels. More often than not, the water conditions will be responsible for this condition.

When fish rot affects fish especially when they live in small tanks, their tanks could become polluted and the infection could set in. this can cause their fins to deteriorate and as a result, their stress levels increase sporadically.

Different fish can suffer from fish rot and stress factors in the fish tank can be responsible. Overcrowding, fin nipping, and changes in the environment are some of the factors that could cause the fin to deteriorate and increase the stress level of the fish.

– Loss of Appetite

Moving into a new tank might be stressful for your fish at first and this might take a while. It could take a while for the fish to calm down and make themselves feel at home in their new abode. This is also typical of humans sometimes. So, if you just switched environments for your fish, this could be responsible for the stress the fish is going through.

It might however be a different story if a healthy fish just suddenly stops eating. So, you could try out some other food apart from what the fish is rejecting. If after a few days, you still notice a loss of appetite, then something is wrong with your fish.

This could also have been caused by an increase in the stress level of the fish.


A stressed fish can exhibit different behaviours that it would not normally exhibit when it is stressed. When your fish is stressed, there could also be notable changes in colour. We have been able to cover some other signs for you to know if your fish is truly stressed.  

Written by Justin Michaels

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