Why Do Goldfish Huddle Together? (Main Reasons)

Why Do Goldfish Huddle Together? (Main Reasons)

Image of goldfish huddling together

Goldfish usually huddle together when they are stressed. Various conditions such as an overcrowded tank, poor water quality, lack of food, heavy water flow, the presence of bullies, changes in the water temperature, or unfavorable environmental conditions cause the goldfish to huddle together.

Let’s understand this huddling behavior in more detail now.

Is It Normal For Goldfish To Huddle Together?

Goldfish are easy-going, hardy fish that adapt to most environmental conditions.

They are active, social fish that enjoy swimming all over the tank.

You will even see them interacting with other fish, digging the substrate, uprooting plants, and playing in the tank.

Now, your goldfish may occasionally retreat to a corner of the tank and rest when they are tired.

However, they will resume their normal activity after a brief period of rest.

Hence, it is highly unusual for goldfish to huddle together and display restricted activity levels for too long.

Huddling is a coping mechanism in most types of fish.

When fish stay together in a group, it makes them feel safe and secure.

Fish usually huddle in groups when they are faced with danger.

Staying in a group also reduces the risk of being caught or harmed.

So, if your goldfish seem to huddle together all the time, you can suspect some trouble in the tank.

Reasons Why Goldfish Huddle Together

Whether you keep your goldfish in a bowl, a tank, or a pond, it will roam around.

If it discontinues this activity and suddenly hangs around in a corner of the enclosure, it indicates a problem.

Stress is the most common cause of this type of behavior. So let’s look at what can cause them stress.

Given below are the main reasons why goldfish huddle together.


Goldfish need plenty of space to swim freely. They don’t like to live in overcrowded tanks.

If you keep your goldfish in a crowded tank, the lack of space will make it feel stressed.

Additionally, overcrowded tanks are also prone to water quality problems.

A spike in nitrite and ammonia levels of the water will add to the stress of your goldfish.

Instead of keeping too many fish in a small tank, upgrade to a bigger tank or separate the fish into different enclosures so that they have enough space and resources to thrive.

Poor water quality.

Goldfish are messy fish. Compared to other aquarium fish, they produce more waste.

Their waste contains high levels of ammonia and nitrites.

Now, the build-up of waste in the water will lead to ammonia and nitrite spikes in the water.

This will adversely affect the health of goldfish as they are sensitive to toxins in the water.

Hence, it’s imperative to maintain good water hygiene in a goldfish tank.

Since toxins like ammonia and nitrites dissolve in water, the water in your fish tank will look the same.

You can only ascertain the presence of such toxins with the help of a testing kit.

Regular water changes will help you keep the toxin levels under control in a goldfish tank.

Additionally, upgrade your filter to meet the needs of your fish and clean the filter regularly to keep it functioning efficiently.

Poor nutrition.

The quality of food you offer your goldfish plays a big role in keeping them healthy and happy.

Overfeeding and underfeeding are detrimental to their health.

Overfeeding poor-quality food will harm the digestive function of goldfish. They will produce excess waste when overfed.

Unhealthy food will also trigger bloating and gas in these animals.

These conditions will make the fish uncomfortable and affect their normal activity.

To avoid these problems, choose healthy, balanced food for your fish.

Avoid using poor quality or old store-bought fish flakes or pellets that expand upon contact with water.

These can cause digestive problems like bloating and constipation.

Include fiber-rich food in their diet to prevent gas formation and pay close attention to the amount of food you feed your fish.

Heavy water current.

Although goldfish are active swimmers, they don’t do well in water with high flow.

Fancy goldfish find it very difficult to swim against strong currents because of their long fins and tail.

If your filter is strong and creates heavy water flow, it can affect the ability of your goldfish to move freely.

If your goldfish constantly swim against the current, they will become tired and stressed.

As a result, the fish may choose to hang out at the bottom where the current is at its weakest.

If your fish swim to the surface of the tank only at feeding time or look pressed against the glass, check the flow rate in your tank.

Reduce the flow to suit your fish, and they will resume normal activity.

Unfriendly tank mates.

The long flowing fins and tails of goldfish attract various aquarium fish.

Fin-nippers may attack your goldfish and bite or tear their fins and tail.

So, if you keep goldfish with barbs or guppies, these fish may bite and nibble on their fins and tail.

The goldfish will try to avoid this attack by trying to hide from the other fish.

All your goldfish may hang out together. The presence of large and aggressive fish will also cause similar behavior.

To avoid such problems, check if your goldfish is compatible with the other fish in the tank before keeping them together.

If problems arise later, you should consider moving the goldfish or the other fish to a different tank.

You can also offer plenty of hiding places in your tank for your goldfish to avoid enemies.

Change in water temperature.

Goldfish are cold-water fish that prefer temperatures in the range of 60°F to 74°F. Therefore, they don’t need heated aquariums.

Now, goldfish are vulnerable to a sudden increase or drop in temperature.

If the water temperature of their surroundings suddenly reduces, the fish become slow and lethargic.

They may go into hibernation mode where their activity levels reduce.

In these conditions, you may notice that your fish merely hover at the base of the tank.

In a large goldfish tank, if you set up a water heater at one end, the heat will not be uniformly dispersed.

As a result, when the surrounding temperature falls, the fish will seek out corners with a comfortable water temperature.

So, all your fish may end up spending their time in such pockets.

To fix this problem, use a heater that evenly disperses heat in the tank.

You can also use two heaters for a large tank to ensure uniform temperature conditions throughout the space.

Unfavorable environmental changes.

Loud noises, harsh lights, and sudden, unexpected movements like banging or jerking the tank can frighten goldfish.

Such disturbances can lead to stress and the fish will huddle together until the danger passes.

If you notice your fish huddling together after being subjected to such disturbances, it is wise to move their tank.

Place your aquarium in a low-traffic area, away from harsh lights and loud noises.

Ensure that it sits on a stable surface that is not prone to sudden movements.

Your goldfish will happily swim around and enjoy their surroundings in such quiet, peaceful spaces.

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