Can Fish Have Feelings Of Jealousy? Observation Says So



  • Behavioral changes show that fish have feelings of jealousy.
  • If extra attention is given to other fish then fish may feel jealous.
  • Food or shelter competition, diversion of owner’s attention towards competitors and water changes are some causes of jealousy among fish.

Fish is a tiny, cute, sentient creature who feels jealousy of other fish. Your fish can show strange behavior or signs of jealousy.  If you add another fish into an aquarium and give her extra care or attention, surely other fish will start to feel jealous.

So, Can fish have feelings of jealousy? The answer is simply yes.

There are some ways through which you can assess that your fish has feelings of jealousy. In this blog post, we will discuss these ways to observe aquarium fish.

Let’s Start.

Can Fish Have Feelings Of Jealousy? Observation Study

Yes, it is correct. Fish get jealous. If various types of fish are present in your aquarium, give similar care or attention to them.

We have observed the jealousy in fish in our aquarium. We bought seven Goldfish two years ago and placed them into our beautiful aquarium.

After almost one month, my friend told me that she wanted to take a particular tiny cute goldfish (my Sushi). She said, “Can you please give it to me” I agreed.

She kept that one goldfish in a small bottle aquarium. After spending one month with the other six goldfish in a luxurious aquarium, that poor fish was jealous. Fish started to bump herself into the walls of the bottle and stopped eating.

After two days, my friend gave that goldfish back to me. And when I took my goldfish back to a similar aquarium, she was happy.

So, never do that.

Jealous fish start bumping the head on the walls of tank - Can fish have feelings of jealousy and insecurity

Conditions Due To Which Fish Feel Jealous

Fish have feelings and they may get jealous. Here are the conditions in which fish can have feelings of jealousy and insecurity.

1. Addition of  Another Fish into the Aquarium

It is a common misconception that fish don’t experience emotions like jealousy.

However, a study published in the Journal of Fish Biology suggests that fish do indeed experience emotions like jealousy and aggression.

For immediate breeding, some owners adopt a strategy in which they place two fish, one male and one female, into a large fish tank. Sometimes, both fish don’t make interaction with each other.

If the fish is not paying attention to other fish, owners add another male or female fish into the same tank. Due to the addition of another fish, one fish get jealous of the other.

The male fish will swim around new fish if a female fish is added. The already present fish will start to feel jealous.

You can observe her jealousy through irregular swimming patterns. Jealous fish will be looking outside the tank the whole day.

2. Extra Attention is Given to Other Fishes

Fish can feel jealousy if an owner provides more attention to other fish and ignore him/her.

Have you ever noticed that when you pay attention to one fish, then that fish get excited? You can observe this behavior of fish. The excited fish changes its swimming pattern and moves in a circle near the tank wall.

Ignoring a fish may develop a feeling of jealousy and insecurity in fish.

The other fishes in the tank have the ability to notice this behavior. Therefore, they start to get jealous of the excited fish. Not only do they notice but also try to attract owners’ attention towards themselves. For this purpose, the jealous fish strikes the excited one.

It could be dangerous. If you give attention to one fish, other fishes may get jealous and ultimately harm or kill the excited fish that is getting your attention.

3. Food & Shelter Competition

Animals don’t have moral values as humans do. For instance, if there is a shortage of food in the habitat of animals, they can eat each other. Insecurity and jealousy is the reason for competition in the animal habitat.

The competition for food and shelter is one of the reasons for jealousy or insecurity. It is similar to humans. Humans may feel jealous of a person with a good meal or shelter. It is the nature of organisms. Fish has a brain, so feelings of jealousy are also observable.

In the case of food or shelter competition, the insecurity condition worsens. The fish of the same species can also kill or harm each other in jealousy to get food.

If there is plenty of food for every fish in the aquarium, the environment of your aquarium will be peaceful. But, if food is deficient in the aquarium, the feelings of aggression or jealousy among the fish will be prominent.

Similarly, the addition of new fish can also lead to an increase in competition. The already present fish will prevent new fish to eat their food. There is a chance that newer fish could be jealous of other fish.

Note: To avoid an unfavorable environment in your aquarium, add sufficient food according to fish numbers.

4. Diversion of Owner’s attention to Competitors

Some owners keep such fish in their tank that eats algae and helps them to clean the aquarium. Tangs are the most common example of algae eater fish. These fish clean the waste algae by eating them.

If these fish don’t perform their job effectively, the owner adds crabs or snails into the water tank. The crabs and snails are also algae eaters and perform the responsibility of Tang fish.

These crabs or snails facilitate the owner by cleaning the aquarium. Therefore, the owner pays more attention to them instead to the fish. In that case, the Tangs get jealous. They start to swim randomly.

If the owner ignores the frustrated Tang, jealousy and envy could increase.

5. Water Changes

The lifestyles of fish vary from specie to specie. Some fishes can live in a small volume of water while other requires plenty of water.

For example, Goldfish cannot live in a small tank. If you keep 2 to 3 Goldfish in a small tank, the friendly goldfish may get aggressive and jealous.

These types of fish require a large volume of water to survive happily. Similarly, most freshwater fishes love to live in plenty of water.

If an owner keeps 2 to 3 fish in a large tank, then these fish become addicted to that environment. After some days, when he shifts one fish to a small tank, feelings of jealousy will originate in that fish.

The jealousy will be noticeable in their actions. The jealous fish will swim constantly and irregularly. It will strike the wall of the water tank.

Do Betta Fish Get Jealous? – The Fighting Fish

Guppies and betta (Siamese fighting fish) – are the species that are considered one of the most jealous fish. Therefore, keeping both fish in the same tank is not recommended.

Betta fish are commonly known as Siamese fighting fish. As their name suggests, they have aggressive behavior. Guppies undoubtedly get more attention than betta fish due to their beauty and friendly attitude. Bettas get jealous due to lack of attention.

Betta fish can have feelings of jealousy for guppy

If you show more affection toward guppies, you will promote envy or jealousy in bettas. This jealousy may cause a war between guppies and betta.

There is an excellent chance that betta- the fighting fish will win the war and your favorite guppy may die.

So, don’t keep guppies and betta in a single tank.


Fish can feel jealous of other fish or their competitor. You can easily observe this feeling in your aquarium fish.

Clearly, jealousy is not unique to humans but is quite widespread in animals. So the next time you see two fishes fighting over a mate, you can be sure they are experiencing jealousy.

Observe this feeling in your aquarium fish and share your experience with us through comments.


  1. Warren, E. W. (1973). The effects of relative density upon some aspects of the behavior of the guppy—Poecilia reticulata (Peters). Journal of Fish Biology, 5(6), 753-765.
  2. 20+ Effective Saltwater Algae Eaters for Your Marine Tank by Peter Herzog.
  3. Can goldfish live in a bowl? Why bowls are cruel by Adam Jones.


  • Frank R. Snow

    Frank R. Snow has two hobbies. First, aquarium fish keeping while writing is the second. He has been an aquarist for the past nine years; therefore, his love for fish is extraordinary. He shares the fish’s feelings. So, together we will make the life of our underwater friends easy.

    Snow Frank R.

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