Why Do My Neon Tetras Keep Hiding? (With 5 Quick Solutions)

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Neon tetras are a beautiful addition to fish tanks. That is why I got disappointed when the school in my tank always chose to hide. Luckily, over the years, I learned why this phenomenon occurs and how to overcome it.

Neon tetras typically hide due to inadequate water conditions, including pH, temperature, ammonia, and nitrates. However, tetras will also feel insecure and choose to hide when carrying a disease, sharing the tank with aggressive tankmates, such as cichlids, or when their school is too small.

As we proceed, I will show you how to deal with neon tetras that refuse to leave their hiding spots. That includes using the API Aquarium Test Kit (link to Amazon) to measure the current pH, ammonia, nitrates, and nitrites in your tank.

Why do my Neon Tetras Hide?

People buy neon tetras because they want to observe them as the creatures dart all over the tank. Therefore, a neon tetra that is always hiding defeats the purpose of the reason you bought it in the first place.

Neon tetras can go into hiding for one or more of the following reasons:

1. They are New to the Tank

Some people are surprised because their neon tetras were so active in the pet shop, but they became timid and shy and ultimately went into hiding the moment they reached the home tank.[1] This is expected behavior.

Neon tetras are active and friendly in pet shops because they are accustomed to that environment. The transition to a new tank is not only stressful but frightening. Neon tetras may go into hiding because they don’t feel secure in their new home. They won’t come out of hiding until they settle.

Your new neon tetras are not the only creatures that hate transitions to a new tank. The neon tetras already living in the new tank may respond negatively to their new neighbors.[2] That is either because they hate the sudden change or because the new neon tetras have personalities that vary drastically from what they know.

Take a moment to determine whether the hiding neon tetras are new or old. If they are new, they are probably struggling to come to terms with their new environment. If they are older, the presence of new fish has probably shaken them.

Also Read: Stress In Neon Tetras

2. Aggressive Tankmates

If you haven’t added any new fish to your tank, consider the larger, more aggressive fish in the aquarium. Neon tetras that are being bullied won’t hesitate to go into hiding, especially if you have an abundance of hiding spots in the tank. The bullied neon tetras will remain out of sight so long as the hostile fish threaten them.

3. Lack of Hiding Spots

As was noted above, neon tetras will hide if they have bullies in the tank. But what if they don’t have conventional hiding places like plants in the tank? The absence of plants and decorations can induce stress in neon tetras. 

That will compel them to hide behind the other objects they can find in the aquarium, including the filters, gravel, heaters, etc. The presence of hiding places puts fish at ease. It lets them know that they can disappear from view if they encounter a threat. Naturally, the absence of hiding places achieves the opposite result.

Also Read: Why Do My Neon Tetras Stay At The Bottom Of The Tank?

4. Small Groups of Neon Tetras

The absence of hiding places isn’t the only factor that can make fish feel less secure. Loneliness tends to do the same thing.[3] Neon tetras are very social, which means that they are happiest in large schools. 

The larger the group, the safer they feel. Social fish like neon tetras are more likely to hide if they are alone or in small groups. If they cannot rely on their numbers to keep them safe, they will hide to avoid confrontations with larger fish.

5. The Tank is Overcrowded

While neon tetras prefer large groups, they do not appreciate overcrowding. That tends to generate aggressive behavior in many species, most of whom manifest territorial attributes. Small fish like neon tetras that cannot fight to secure their territories will go into hiding to avoid the conflicts that will eventually break out.

6. Inadequate Water Conditions

Like most fish, neon tetras do not appreciate changes to the conditions in their tank.[4] Naturally, the wrong parameters, including the pH, hardness, and temperature, will drive them into hiding. But the same is true for sudden changes in those parameters, even if those changes are for the better.

For instance, some neon tetras live in abysmal conditions because their owners have failed to maintain their tanks appropriately. However, you cannot help those neon tetras by suddenly altering their conditions to provide their tank with the correct parameters.

Because the creatures are accustomed to the poor conditions, even a change for the better will harm them, causing the sort of discomfort that will compel them to hide. Changes in an aquarium should be gradual.

7. Diseases & Injuries

Like most fish, neon tetras are vulnerable to various diseases, including dropsy, ich, swim bladder disease, fungal infections, etc. Sick neon tetras are more likely to remain in hiding because their illness makes them vulnerable to predators.

Like a disease, injuries make neon tetras vulnerable. If a scuffle with another fish or a collision with an object left a neon tetra with a wound, it would remain in hiding until its condition improves.

8. External Stimuli

Sometimes, neon tetras go into hiding because of the stress that external stimuli have induced in them. That includes bright lighting in the room in which the tank is positioned, the lights in the room going on and off frequently and at unexpected times, the presence of human traffic, loud voices, loud television sets, people tapping on the glass, etc.

What to do with Neon Tetras that Always Hide?

Some neon tetras hide because they want to. They have a personality trait that makes hiding enjoyable and preferable for the creatures. But if you are convinced that external factors are forcing your neon tetras to remain in hiding, you can use the following methods to help them:

1. Adjusting the Water Conditions for Tetras

Neon tetras tend to go into hiding whenever they encounter discomfort. You can keep them happy by maintaining optimal conditions in the tank. 

That means carrying out regular water changes, checking all your hardware (such as the filter, heater, and pumps) to ensure that they are working as expected, and removing pollutants like waste and uneaten food to prevent ammonia and nitrite levels from spiking.

It also means maintaining the right temperature, which should be 70 to 78 degrees F. And as was mentioned, the temperature should be stable and feature no fluctuations. To achieve that, I personally use the Orlushy Submersible Aquarium Heater (link to Amazon).

The suitable water pH for tetras is between 6.0 and 7.0.[5] You can accurately measure it by using the API Aquarium Test Kit (link to Amazon). That is the product I picked for my tank since it also tells you the ammonia, nitrates, and nitrites levels. And the best thing is that it lasts for over 800 measures.

A clean, well-maintained aquatic environment with the appropriate parameters will encourage your hiding neon tetras to come out. If you have to make changes to the tank, do so gradually. Raise or lower the pH and temperature slowly so that the alterations are not too jarring.

Also Read: Neon Tetra Tank Setup

2. Add a Few Plants

It sounds counterintuitive, but if you want your fish to spend less time hiding, you have to give them more hiding spots. The goal isn’t to compel them to hide. Instead, plants like java moss and hornwort will let them know that they have a sanctuary that will keep them safe from predators and prying eyes if the need arises.

This will combat stress in the tank. You can also add rocks, driftwood, seashells, and the like.[6] Remember to clean all these objects before you add them to the tank. Otherwise, you will introduce bacteria and parasites.

Also Read: 11 Plants Your Neon Tetras Will Love In Their Tank

3. Pick the Right Number of Tetras

Tetras should live in groups of at least six.[7] Add as many neon tetras as you think are necessary. But the tank size has to match the number of fish. Neon tetras require at least 10 gallons. Anything smaller may crowd them, a development that will force them back into hiding.

4. Choose the Right Tankmates

Get your neon tetras some suitable tankmates. You can always combat bullies by giving the fish places to hide. However, that will only encourage your neon tetras to stay out of sight, which you don’t want. If you want your neon tetras to swim out in the open, remove the bullies. Get the neon tetras suitable neighbors such as harlequin rasboras, zebra danios, guppies, etc.[8]

Also Read: 19 Great Neon Tetra Tank Mates

5. Treat New Fish Properly

Neon tetras in new tanks shouldn’t concern you. Once they are comfortable enough in their new environment, they will come out of hiding. You should only act if your new tetras have spent a week or more in hiding. 

In such cases, you should study your tank to identify any factors contributing to their sense of fear, including bullies, the absence of suitable hiding places, and the presence of toxins. All this assumes that you took the time to acclimate your neon tetras. 

Many aquarists use the drip method to expose their new fish to the conditions in the aquarium they will soon inhabit. This protects them from any shock they would typically experience if you threw them into the new tank without acclimating them.

  • Here is a helpful Youtube video that talks all about the dripping technique:

How Can You Tell if a Neon Tetra is Stressed?

These signs indicate that a neon tetra is stressed:

  1. Stressed neon tetras will spend most of their time in hiding.
  2. The fish display erratic swimming behavior; some neon tetras will zip all over the tank. 
  3. The tetra will gradually become less active. Eventually, it will lay still at the bottom.
  4. You may observe labored breathing in stressed tetras, with some gasp at the surface.
  5. Stressed neon tetras will stop eating and won’t respond to food.
  6. The fish will become discolored over time, especially if their original color was bright and vivid.

Also Read: Why Is My Neon Tetra Gasping For Air?

If you noticed these signs in your neon tetra, you should definitely take action. Keeping the fish in its current situation will compromise its health and general state. That also applies to its tankmates, which probably suffer as well.


If your neon tetras consistently hide, I highly recommend trying to fix it. That is how the fish tells you, without speaking, that something went wrong. Start by observing the fish’s environment and its interactions with the rest of the fish.

Next, measure the aquarium parameters, pH, temperature, and ammonia in particular. If they are out of range, conduct more frequent water changes (and do it gradually). Ultimately, you may add vegetation or a few more tetras to make them feel more secure.


  1. https://www.thesprucepets.com/why-do-my-fish-hide-all-the-time-1380775
  2. https://kniselys.com/blog/58665/why-are-my-fish-hiding-now
  3. https://tetra-fish-care.com/why-is-my-neon-tetra-hiding/
  4. https://www.thepondguy.com/product/learning-center-wg-why-fish-hide/learning-center-wg-fish-care
  5. https://www.vivofish.com/neon-tetras/
  6. https://aquariumsathome.com/do-neon-tetras-need-hiding-places/
  7. https://modestfish.com/neon-tetra/
  8. https://modestfish.com/neon-tetra-tank-mates/