Why Do My Fish Stay In One Spot? 9 Reasons & Solutions

Have you ever observed your fish staying in one spot in the aquarium and wondered why they're not exploring their environment? Many fish owners experience this behavior and can become concerned about the well-being of their aquatic pets.
Why Do My Fish Stay In One Spot?

We’ll delve into the reasons behind this behavior and discuss how to fix this issue, so your fish will be swimming around exploring their home in no time!

Why Do My Fish Stay In One Spot?

Fish behavior can be influenced by a variety of factors which can cause them to remain in one area of their tank. Some of the reasons include lousy water quality, temperature, flow, tank mates, health, and even personal preference.

By understanding the various elements that contribute to your fish’s stationary behavior, you can take action to provide the ideal environment for them to thrive.

9 Reasons Why Fish Stay in One Spot

The 9 most common reasons your fish is swimming in one spot are:

1. Tank Size

A tank that is too small for the number of fish or the size of the fish may force fish to stay in one spot due to a lack of space.

2. Poor Water Quality

Poor water quality can cause fish to stay in one spot. High ammonia levels, improper pH levels, or other imbalances in water parameters can stress out fish, making it hard for them to swim freely.

If you have fish that are staying at the top of the tank, laying on the bottom of the tank, or near filter outputs could be a sign of having low resolved oxygen levels. Those places are where oxygen concentration is generally higher.

Different fish prefer different water flow rates. Strong currents or stagnant spots could cause your fish to stay in one area that best matches their preferences.

A filter that is underpowered or in need of a good cleaning won’t be able to clean the water as efficiently.

3. Water Temperature

Fish are cold-blooded, which means their body temperature matches their surroundings.

If the water in your tank is too cold or too warm, your fish may stay on one side of the tank as that side has a more comfortable temperature for them.

4. Aggressive Tank Mates

Fish will seek out hiding spots to avoid aggressive tank mates that display territorial or bullying behavior.

Larger fish tend to give smaller fish a hard time. In the fish world, anything that will fit in another fish’s mouth is considered food!

5. Disease and Parasites

A sick or stressed fish may become lethargic and stay in one spot due to illness or parasites. 

Some of the most common fish diseases are:

Fancy goldfish are notorious for floating upside down at the top of the water, usually right after feeding.

It should right itself within a couple of hours of feeding, their swim bladder gets overinflated due to excess air being swallowed whilst feeding (greedily!).

The best way to avoid this is to feed them food that sinks in the water.

6. Sleeping

Fish need to rest too! They may stay in one spot while catching up on sleep.

Fish sleep patterns can vary depending on the species and whether they are nocturnal or diurnal.

7. Breeding

Some fish may stay in one spot during the breeding process. They could be tending to eggs, engaging in courting behavior, or settling into breeding territories.

Pregnant fish may seek out specific spots to rest or give birth. If you notice your fish lingering near breeding areas, it may be preparing for the arrival of its offspring.

8. Poor Diet

A poor diet can lead to malnourishment and general weakness, causing the fish to stay in one spot.

9. New Fish

New fish can take a while to adjust to their new home and may stay hidden in one spot until they feel more confident that it’s safe to explore the tank.

9 Ways To Stop Fish Staying In One Spot

Now you know what may be causing your fish to hang out in one spot of the tank, let’s look at what you can do to fix it.

1. Don’t Overcrowd Your Tank

Overcrowding in fish tanks can be a common issue, causing your fish to stay in one spot rather than swimming around and exploring their environment. I’ve covered this in more detail in my post about overstocking your fish tank.

Too many people don’t consider that the cute tiny fish they buy in the pet store will grow, and possibly grow very big.

The chart below lists some popular pet fish, their full size, and the minimum tank size they’ll need when fully grown.

Angelfish6 inches30 gallons
Betta3 inches5 gallons
Discus8 inches75 gallons
Fancy Goldfish5 – 10 inches20 – 30 gallons
Guppies2 inches10 gallons
Mbuna African Cichlids6 inches55 gallons
Neon Tetra1.5 inches10 gallons
Oscar14 inches75 gallons
Tiger Barbs3 inches30 gallons
Zebra Danios2 inches10 gallons

I’d always advise using a reliable aquarium stocking calculator to work out if you’ve overstocked your aquarium or not.

2. Keep The Water Clean & Healthy

Once you’ve got your stocking levels worked out, you need to ensure the tank water is kept clean. Your fish don’t just swim in the water, they breathe it.

You’re going to need an appropriately sized filter. When it comes to the size of tank aquarium filters are rated for, there is no standardized system in place, and it can vary a lot between the different manufacturers. It’s very much like how clothes can vary in size from one brand to the next.

To keep things simple, I’ve always worked on the basis that a filter needs to be able to turn over the volume of water in your tank 5 times per hour. This will stop you from buying a filter that’s either too small or too powerful (and save you wasting your money) for your aquarium.

Check out the chart below to work out how much filtration you’re going to need.

20 100 g/ph 200 g/ph
29 145 g/ph 290 g/ph
40 200 g/ph 400 g/ph
55 275 g/ph 550 g/ph
75 375 g/ph 750 g/ph
90 450 g/ph 900 g/ph
100 500 g/ph 1000 g/ph

You’re also going to need a water test kit so you can monitor your tank’s water quality and keep it in optimal condition.

API Freshwater Master Test Kit

You should test and record your water parameters regularly so you can spot the early signs of something not being right.

Aim for the following levels in the tank:

pH Match your specific fish’s requirements
Ammonia 0 ppm
Nitrite 0 ppm
Nitrate Below 20-40 ppm

If your water pH level is too high, I have listed the best ways of lowering aquarium pH levels naturally and safely.

Once your nitrate level rises above 20 ppm (some people say 40 ppm, 20 ppm is my preference), you need to perform a 25% water change.

The best tool for the job is the Python No Spill and Fill gravel vacuum, it makes cleaning and water changes a breeze.

Python No Spill And Fill

I have a detailed guide on keeping your tank clean.

3. Ensure Even Water Temperature Throughout the Tank

Uneven water temperature in the tank can cause your fish to stay in one spot due to their preference for a specific temperature range.

To ensure a consistent temperature throughout the whole tank, you can use a reliable adjustable heater, such as the Fluval E Series, and a good-quality thermometer.

Fluval E100 Aquarium Heater
ZACRO 2 Pack Digital Aquarium Thermometer

Check the tank temperature regularly and make any necessary adjustments.

4. Add Plants & Decor to Provide Hiding Places

Adding plants and decorations to your fish tank can help your fish feel more secure and comfortable, which can encourage them to explore and move around more freely.

Make sure to add a variety of plants, rocks, driftwood and/or caves to give them plenty of hiding places.

Live plants, like pothos, do a great job of soaking up excess nitrates, but if you’re not green-fingered you can get some good quality plastic or silk plants these days.

5. Ensure Any New Tank Mates Are Compatible

If you add any new fish, ensure you research beforehand that they are compatible with your existing fish.

If you have any shy fish that hide away, adding dither fish can be a great solution, as they encourage more timid fish to feel safe and secure.

6. Feed Fish A Quality Diet & Feed At the Same Time Each Day

Fish can become accustomed to a feeding schedule. By feeding your fish at the same time each day, they may associate that time with food, which can encourage them to move around and be more active.

Offering a varied diet with high-quality, nutritious food can also impact your fish’s overall health and activity level.

Research what specific nutrients and types of food your fish needs, and make sure to provide them with a balanced diet.

If you want to spoil your fish, I have some quick and easy homemade fish feed recipes that your fish will love and you know exactly what’s in it, no hidden nasties!

7. Fix The Water Flow

The water flow in your tank can be adjusted to create a more comfortable environment for your fish.

A gentle flow allows your fish to swim without exerting too much energy, while a stronger current can encourage movement. Be sure to research your specific fish’s preferences to ensure the optimal water flow.

A general rule of thumb is that if your fish has long-flowing fins or is not very streamlined (like Bettas or fancy goldfish), they prefer a gentler flow.

Either adjust your filter’s flow rate or add decor items to break up the water flow.

8. Add A Bubbler To The Tank

Adding an air pump and bubbler/air stone to your tank will help keep enough oxygen in the water, which is essential for your fish’s health.

A well-oxygenated tank may encourage your fish to move around and explore more, as they will feel more comfortable and energized.

If you see fish gasp for air at the water’s surface, or laying still on the bottom of the tank, it could be a sign that your water lacks dissolved oxygen.

9. Treat Sick Fish

This goes without saying, but if illness or injury is the reason your fish stay in one place, you need to take action immediately.

Depending on the injury or illness, you may be best isolating and treating the affected fish in a quarantine tank or you may need to treat the entire tank (e.g. for an ich outbreak).

If you would like to seek veterinary advice you can find a specialist aquatic vet in your area using these links:


If A Fish Stays Still Does That Mean It’s Dead?

Not necessarily. While a dead fish will indeed remain motionless, a living fish can also stay in one spot for various reasons.

These reasons could include water temperature, stress, or sleep. However, if you notice additional signs such as a lack of appetite, discoloration, or an unnatural position in the tank, it’s time to investigate further to determine the health of your fish.

If A Fish Is Staying Still Does That Mean It’s Sleeping?

It’s possible! Fish don’t have eyelids like us, so it might be a little tricky to spot them sleeping.

When fish sleep, they tend to stay still and reduce their activity. If your fish is staying in one spot and appears to be in a “resting” state, it could be sleeping.

Just like humans, fish need some shut-eye too, and this is a normal and necessary behavior for their overall well-being.

Is Your New Fish Staying In One Spot?

Introducing a new fish to a tank can be stressful for the newcomer. If your new fish is staying in one spot, it’s likely trying to familiarize itself with the new environment and find a safe place to hide.

Keep an eye on the fish and give it a few days to adjust. It should gradually start swimming around the tank and interacting with its new tankmates.

Why Is My Fish Always Hanging Near The Filter?

Fish might be hanging near the filter for a few reasons.

First, it could be that the fish enjoys the flow of water produced by the filter. Some fish species are naturally attracted to currents and might find this area more comfortable.

Second, the filter could provide a sense of safety, as it offers a place to hide from other fish or perceived predators.

Lastly, poor water quality. The filter outlet might be providing a source of dissolved oxygen for your fish to breathe.

Regularly testing your water and maintaining your aquarium will help ensure a healthy environment for all your fish.

Closing Thoughts On My Fish Is Staying In One Spot

You’ve now learned some of the reasons why your fish may be staying in one spot. It could be due to temperature fluctuations, water quality issues, or simply because they are sleeping.

Cleaning your tank properly and keeping an eye on water parameters like ammonia, nitrite, nitrate, and oxygen levels will all help to maintain a healthy environment for your fish.

If you still notice your fish spending most of their time in a single location, your fish may be sick. You should consider isolating the sick fish in a hospital tank and consulting with a veterinarian specializing in fish to rule out any possible health issues.

If you would like to seek veterinary advice you can find a specialist aquatic vet in your area using these links:

Always prioritize the welfare of your fish. A happy and healthy fish will bring joy to your home!

Check out the Aquarium Health section for more guides just like this one.

Picture of Paul


Hey, fellow fish enthusiast 👋! I'm Paul and I've been an aquarium addict since I won my first goldfish at the fair many years ago. Let me share with you the knowledge that I've gained along the way (and avoid the mistakes I've made!), so you too can create an underwater paradise for your aquatic friends.