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Why Is My Red Tail Shark Hiding? (9 Common Reasons)

Why Is My Red Tail Shark Hiding? (9 Common Reasons)

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This post is written to the author's best knowledge and is not intended to be used in place of veterinary advice. In addition, this post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.

Red tail sharks are one of the best fish species to keep in a home aquarium. These aquatic creatures aren’t just visually pleasing—they have rare and fascinating behaviors, too.

These freshwater fish have the fiercest of personalities and will tirelessly chase other fish to defend their precious territory. However, red tail sharks can sometimes act the opposite way, showing signs of timidity and isolation.

As a concerned pet owner, you might be wondering: Why is my red tail shark hiding?

If that’s the case, then this guide is for you! Keep reading to discover the most common reasons why your red tail shark is acting more elusive and shy than usual.

1 – Natural Behavior

Unlike other fish species that tend to get lonely, red tail sharks are solitary creatures. They love having their own space and have no problem spending time inside caves and other structures.

That said, just because your red tail shark is hiding doesn’t necessarily mean something is wrong. Timidity is one of this species’ signature traits, and it’s most often observed during their childhood phase.

Usually, these creatures only come out to feed and are shy around other aquatic animals. However, once they reach their adult stage, they become dominating, aggressive, and territorial.

If your pet is showing signs of good health and its habitat is in suitable condition, then it may just be hiding out of instinct.

2 – Poor Water Quality

Red tail sharks are surprisingly sensitive to the water quality in their tank. Unfavorable water conditions can cause them to become stressed and hide.

To prevent this, maintain the correct water quality in your aquarium. Stability is also important because sudden fluctuations in the water temperature, cleanliness, and pH levels can cause your pet to get sick.

Monitor your pet’s water supply regularly to ensure proper oxygen levels, stable parameters, and a strong filtration system.

3 – Overcrowding or Lack of Space

The ideal tank size for your pet is 55 gallons, with a ratio of only one red tail shark per tank. These territorial creatures act aggressively even to members of the same species and find it difficult to mate because of this unique behavior.

When your tank is too small or overcrowded with fish, your red tail shark may become frustrated and unhappy. With no room for exploration and roaming, your pet will likely hide to avoid clashing and confrontation with other fish.

4 – Inadequate Hiding Spaces

Most fish species, including red tail sharks, need hiding places to feel safe and secure. Hiding is one of red tail sharks’ natural instincts, and the lack of private caves or hideouts can make them feel stressed or threatened.

The simple act of providing a rocky substrate and vegetation for coverage can go a long way in reducing your pet’s shyness and aggressive tendencies.

Additionally, consider adding the following aquarium elements to create hiding spots and markers for your fish’s territory:

  • Floating plants
  • Rocks
  • Driftwood
  • Artificial decorations
  • Terra cotta pots
  • PVC piping

5 – New Tank and Environmental Changes

If you’ve just introduced your red tail shark to a new tank or made noticeable changes to its habitat, then your pet might be hiding out of shock or unfamiliarity. A recently transferred fish could also act shy around the already existing creatures in its new home.

In this case, you’ll need to give your fish some time to acclimate to its new environment and start socializing with tankmates. The exact amount of time may vary, but around one week is reasonable.

During this period, it’s important to make sure that your pet is eating normally. Pay close attention to its health and provide extra care until your pet is comfortable enough to come out.

6 – External Threats

Another possible reason behind your red tail shark’s frequent hiding might be fear or stress from external factors. It’s common for frightened fish to hide from loud noises, movements around the tank, or intimidating fish.

Observe the behavior of other fish and aquatic creatures in the tank to see if they’re bullying your red tail shark. Some owners report that their red tail sharks tend to hide from bigger members of the same species.

Separate aggressive fish from peaceful ones, and make sure that your red tail shark isn’t paired with an incompatible species. Ideal tankmates for red tail sharks are as follows:

  • Bala Sharks
  • Tiger Barbs
  • Zebra Danios
  • Pearl Gourami
  • Neon Tetras
  • Angelfish

If bullying isn’t the case, try relocating your aquarium to a quieter area, and move slowly around the fish tank. Soon enough, your pet will get accustomed to your gestures and won’t feel as threatened as before.

7 – Illness

Sick red tail sharks tend to isolate themselves in their hiding spaces in order to rest and seek protection. This behavior is usually accompanied by a lack of appetite, a dull appearance, and sluggish movements.

Keep your pet healthy by providing it with a healthy diet, ideal water parameters, and optimal habitat conditions. To be safe, inspect your red tail shark’s behavior and appearance daily for any signs of illness.

Common diseases for this fish species include the following:

Fin Rot

This infection stems from unclean water conditions and inadequate oxygen levels in the fish tank. Frayed and tattered fins, discoloration, and inflammation are the usual symptoms of this disease.


Red tail sharks with Ich exhibit salt-like white spots on their body, and they tend to rub themselves against objects in the tank. The cause of Ich is an external parasite called Ichthyophthirius multifiliis.

8 – Too Much Light

Did you know that red tail sharks are nocturnal? These creatures are liveliest at night and prefer dark tanks or aquariums with dim lighting.

Bright artificial lights may look visually pleasing to human eyes, but the high intensity can be uncomfortable for your fish and cause it to hide. As an experiment, try turning off your tank lights to see if it comes out.

Additionally, avoid having direct sunlight in your pet’s habitat during the day. You can also use plants that offer plenty of dense shade to make your pet feel at ease.

Another option would be to install lights that have adjustable day and night settings and a blue light feature. This adjustment might be the key to coaxing your fish out of hiding, so you can enjoy its company more often.

9 – Extreme Water Currents

Red tail sharks appreciate fast, and heavy water flows that resemble their native habitats in swift rivers. These creatures can handle strong currents, but extreme flows and water movement can immediately cause them to hide instead of swimming freely.

For this situation, a quick fix would be to tweak the flow rate of your tank equipment to a more comfortable level. Adjust your filter, bubbler, or oxygenator accordingly.

Other methods of diffusing the flow rate would be to use sponges, driftwood, rocks, or floating plants in your aquarium. Additionally, a redirector fitting might help you control the movement of water to a more desirable rate.

Final Thoughts

Red tail sharks are attractive, unique, and relatively low-maintenance pets. However, their shy, aggressive, and territorial behavior can sometimes confuse owners and cause worry and concern.

Hopefully, this guide has answered your question: Why is my red tail shark hiding?

The most common causes for this behavior include environmental changes, external threats, and overcrowding. You might also need to make adjustments to your tank’s lighting conditions, flow rate, or water quality.

Note that there may be more than one reason behind your pet’s sudden isolation or shyness. As a responsible owner, remember that vigilance and proper care are the keys to keeping your red tail shark healthy, happy, and active.

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