5 Reasons Why Do Fish Chase Each Other and How to Stop Them

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Keeping pets at home is a huge responsibility. You have to consistently care for them, not to mention that you also need to watch their behavior. Although many people think that keeping a pet fish is an easy task, it is far from the truth.

You have to maintain optimal water conditions, feed them on time and keep a check on their well-being. Pair that with their unique behavior traits, and you have so much to do. Besides everything, have you ever wondered why fish chase each other?

Typically, it might seem like the fish are playing around. But, the actual reasons run a lot deeper than that.

This article will explore everything you need to know about the reasons why fish chase each other and how to stop them.

Why is My fish chasing each other in circles?

why do fish chase each other

Maintaining a community tank isn’t an easy task. You have to be mindful of each tank mate, ensure every species gets optimal water parameters and care for them individually and as a unit.

Over time, you will notice certain species of fish chasing each other around the tank. While some like to play around like that, there are other reasons.

Let us explore the top 6 possibilities:

1. Incompatibility

bettas don’t mesh well

Bettas, a very popular aquarium fish species, are very territorial. You won’t find them in schools or shoals in the tank. Not just with other species, bettas don’t mesh well with their kind, not just with other species.

Incompatibility, territorial behavior, and aggressiveness are common reasons your fish is chasing each other in the tank. If a fish feels threatened, it will do everything to eradicate that threat from its vicinity.

Besides bettas, even guppies and goldfish don’t make good tankmates. This way, several fish species don’t mesh well with each other.

So, when setting up a community aquarium, you can’t go into the process blindsided. You have to do thorough research about individual species. The more in-depth and comprehensive your research is, the easier it becomes to maintain the ideal setup.

2. Territorial Behavior and Dominance

betta - territorial behavior and dominance

A very common trait among the same-species tanks, the alpha-male fish tries to exert their dominance with this behavior. For example, in shoaling fish species, the male ones often chase a few from the troop to show their dominance in the group.

Not just in captivity, this is a very common trait in the wild, not just in captivity. This is a common behavior in guppies, where the males are extremely territorial. You will often hear expert aquarists suggesting avoiding adding two male guppies in a tank.

Also, if you have territorial fish species in the tank, always space them out in larger tanks. Often, the male fish will bully the “weaker” ones in the group, leading to chaos in the tank.

Having a larger shoal or school of fish ensures that the dominant fish won’t attack one or two in the group.

Also, the dominance and territorial behavior are at their peak during the breeding season. You will often find a male fish chasing a female one to mate and fertilize the eggs. Stay vigilant during those times to avoid harming the female fish in the process.

3. Mating Season

Mating Season

During the courtship and breeding season, the chasing process among fish increases. If your tank has male and female fish of the same species, you will find the male one chasing the female one. The chasing heightens once the female fish is ready to release their eggs.

However, even with the breeding process, the chasing falls under three distinct categories:

  • Male fish chasing another male fish to exert dominance before mating season
  • Male fish chasing female fish for courtship
  • Female fish chasing a male fish for mating

The aggression among male fish in the species before the breeding season can lead to several complications in the tank. Not paying attention will put the threatened fish under stress and danger.

So, ensure that the tank’s female fish to the male fish ratio is always high. If the tank has more males in them, it can increase the degree of aggression.

4. Feeding Competition

feeding competition among fish

Food is crucial to any ecosystem. Like humans, even fish need an optimal and regular diet to keep them healthy and satiated.

In a community tank, the feeding process can become very tricky. You have bottom feeders, surface feeders, carnivores, omnivores, etc. As a beginner, not being able to manage an optimal feeding cycle for each fish species is common.

When a fish isn’t satiated and still feels hungry, it will target smaller and vulnerable species in the tank. So, competition for food can make one fish chase the other.

Besides preventing other fish from eating their food, extreme cases of such chasing and competition can even lead to fish cannibalism.

Ensure that you always run thorough research about the fish’s optimal dietary requirements and feed them accordingly. The last thing you want is for a vulnerable fish species to become a dominant’s food for the day.

5. Lack of Space

Most fish need and like their space. So, if you build a community tank in a closely-knit space, it will inadvertently enhance the territorial feeling of the fish.

Territoriality is a common reason a fish might chase the other one away. But why is a fish species becoming so territorial?

There could be several reasons, including:

  • Incompatible tankmates
  • Lack of space in the aquarium
  • Too many decorations and plants
  • Lack of vegetation in the tank and so on

After introducing them to the tank, always look out for the fish’s behavior. The last thing you want to do is impose any risks for the fish and worsen the situation.

How To Stop Fish Chasing Each Other?

How To Stop Fish Chasing Each Other

There is only one way to stop your fish from chasing each other – Identify the cause.

Why is your fish chasing each other in the tank? Once you know the reason, it becomes easier to implement the resolutions the right way.

  • If it is a matter of dominance, aggression, or territoriality, you can separate the fish showcasing such behavior.
  • Due to poor tank setup, you can rearrange the entire tank to check what works.
  • If it is due to overcrowding, consider getting a larger aquarium to accommodate all the fish.

The faster you find the reason, the easier it becomes for you to tend to the issue and rectify it before things turn for the worse.

How Do I Know If My Fish Are Fighting or Mating?

Signs of natural dominance, aggressive behavior, and competition in the tank can either indicate early signs of mating or showcase that the fish are fighting.

Whatever the reason is, you need to stay vigilant about the temperament to avoid repercussions. For example, during the mating cycle, the male fish showcases signs of aggression and dominance to catch the attention of the female fish.

However, sometimes, mating and fighting temperaments are very similar. Therefore, it becomes highly difficult to differentiate between the two.

As a beginner, you might have difficulty distinguishing between the two. In such cases, we’d recommend that you take it slow and register the behavior of the fish first.

Unlike mating behavior, where the fish vibrate their body, chase the female and try to establish courtship with them, fighting involves aggression. So if you find a fish attacking another, indulging in fin nipping, it is a sign of fighting.

In such cases, as a fish keeper, you have to work proactively. First, separate the aggressive fish from the tank immediately before they do further damage.

Why Aquarium Fish Fight?

There are primarily three reasons why aquarium fish fight. It is either for food, mating, or exerting dominance in their territory.

While the food and mating situations are still manageable, territoriality is quite a bad trait.

Not only does it induce risks of fights among the same species, but it can put the more vulnerable fish species under threat. This eventually leads to complications like stress and eventual death in the fish.

How to Stop Fish Fight in Aquarium?

Once you identify why your fish in the tank are fighting, you can then implement the right solutions to fix the problem. Following are some effective ways to stop a fight in the aquarium:

  • Separate the aggressive or territorial fish using a net
  • Rearrange the entire tank decorations to prevent further aggression in the fish
  • Add hiding spots with rocks and caves for the weaker and vulnerable fish species in the tank
  • Find the bully in the tank and isolate them in a separate aquarium
  • Avoid overcrowding by getting a larger fish tank
  • During the breeding season, separate the mating pair to another tank

If you find the fish still fighting after these interventions, we’d recommend conducting a water change and researching more into the ideal tank setup.

Wrapping Up

There are several reasons why a fish is chasing another in the tank. However, instead of letting things be and brushing them under the rug, take the necessary steps to correct the complication. Ideally, the quicker action you take, the easier it becomes for you to maintain harmony in the tank. We hope this article gives you all the insights in detail.

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