Fish is hiding under rock: 6 possible causes (with solutions)
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Aquarists may notice that their fishes are hiding under rocks or anywhere else in the aquarium. If you are one of them then from here you are going to know why fishes behave like this. Here I’m going to discuss 5 such possible causes for which your fishes are hiding all the time.
So without wasting much time let’s dive deep into the topic
What are the 6 possible causes for which fishes are hiding under rocks?
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Fishes have got stress
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Fishes are bullied by other tank mates
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Fishes are not habituated still with the environment
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Fishes have got some diseases
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Over-crowding occurs in a fish tank
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During the Hatching times of eggs
Now let’s discuss these causes thoroughly
Fishes have got stress
Stress is one of the bad things which prevent the growth of the fish. So if your fish is hiding under rocks in aquarium then stress can be a cause for it. So at the point you should try to figure this out.
Basically, stress happens for water conditions for fishes. But other factors also insist stress in their body also. Here water condition means water temperature, phosphate level, nitrate level, ammonia level, etc according to the source. If these levels fluctuate frequently then fish will get stressed obviously. So you need to maintain these water parameters by some good tools.
Low oxygen level is one of the bad things to give stress to fishes in aquariums. You should understand the signs of low oxygen level by checking the behaviors of fishes carefully. One of the main signs is to hide under rocks but when it gets more stressed then it will behave weirdly.
Not eating much can be a sign of stress. Another sign can be strange swimming. When you see that fishes are swimming vertically instead of horizontally then you can be sure about the stress of that fish. If your fish is rubbing its fins or mouth or body against gravel or glass then that is the sign of stress of that fish.
Fishes are bullied by other tank mates
Wrong tank mates can give stress to your main fish. So you need to choose the right companion for your main aquarium fish.
Some fishes love to stay with their own kind of fish. So if you keep that type of fish one piece in a whole aquarium then it will feel afraid and it will hide under rocks. For example, you can take tetra or blue ram, etc. These are called school fish and they love to stay with their own community. So keeping a single these types of fish can be a cause of hiding under the rocks.
Another possible thing that can happen is that your fish is being bullied continuously by other strong fish. At that point, the weaker fish will try to find some safe spots in a fish tank. It may feel under the rock is a safe place to hide. So you must know well about the suitable companion of each fish before creating a community fish tank.
Here I can help you by giving some data about it as a chart. So let’s know more about it.
| Fish Name | Tank Companion | Avoid |
| 1. Albino Rainbow Shark | Gourami, Barbs, Danios | Raid tall Shark, Bala Shark, Catfish |
| 2. Neon Tetra | Gourami, Barbs, Dwarf Cichlids | Pearl Gourami, Opaline Gourami |
| 3. Molly Fish | Cherry barbs, Rosy Barbs, Dwarf Gourami, Danios, Harlequin Rasbora | Convict Cichlids |
| 4. Swordtail | Platies, Rosy Barbs, Neon Tetra, and Dwarf Gourami | Jack Dempseys, Convict cichlids |
| 5. Tiger Botia | Neon Tetra, Cherry Barbs, Tiger Barbs, and black widow Tetra | Any predatory fish
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| 6. Guppy | Molly, Peaceful Tetra, Platies. Gourami | Redtail Shark |
| 7. Gourami | Rosy Barbs, Angelfish, Swordtail, Tiger Barbs | Invertebrates |
| 8. Goldfish | Zebra danios, Neon Tetra, Molly | Tiger Barbs |
| 9. Harleyquin Rasbora | Cherry Barbs, Danios, Guppies | Cichlids, Betta |
| 10. Betta | Neon Tetra, kuhli loach, Glass Catfish | Tiger Barbs |
Fishes are not habituated still with the new environment
When you introduce a new environment to fish then that may be painful to a little bit. They may be scared at that time and that’s why they may hide under the rocks or anywhere else in the aquarium.
So you need to know how to introduce fish to a new aquarium. This is not as simple as you are thinking. Here you need to know the process to introduce a new home for your fish.
First, you should remember that try not to wait longer period of time in the road after buying fish from the shop. This period is very painful for fish. So if you want to keep your fish healthy then try to come home as soon as possible after buying.
After that, you need to put it in a bag which is filled with water which is taken from the aquarium where you want to keep that fish. Then that bag should keep hanging up in the middle of the aquarium for 15 to 20 minutes. After 20 minutes you should open the bag after turning off the lights of the aquarium and after a while, fish will come out from that bag and go into its new place. This is the proper way to introduce a new aquarium to a new fish.
But before opening the bag fully you must check the pH level of both the aquarium and the water of the bag inside. Discus is such fish that is very much sensitive to pH level. So you must check some of these parameters before introducing a new fish in a fish tank. Otherwise, it will hide obviously.
Read more:- How to set up a community fish tank with cost analysis
Fishes have got some diseases
Diseases are one of the main causes just why fishes are hiding under rocks or anywhere else in the aquarium.
Just think like yourself. If you feel sick, will you go out of the room? I think no. Fishes are just like you. If it feels sick then it will try to find some safe places inside of aquarium to hide.
So if your fish is hiding under rocks or anywhere else in the aquarium then you should check if it is sick or not. There are some ways to find this issue.
|
Symptoms |
Diseases |
| Murky spots on mouth, skin | Bacterial Infection |
| White blotch on skin | Viral Infection |
| Cotton like white hair on food, eggs, fishes | Water Mold |
| Uneven growth of fins | Carp Pox |
| Inflated eyes, red fins | Bacterial Infection |
| Skin sores | Bacterial Infection |
| Swollen abdomen | Bacterial Infection |
| Increased gill | Parasites |
| Golden spots on the skin | Velvet Disease |
Here I’ve given some symptoms which you should check if your fishes are hiding under rocks or anywhere else in the aquarium. You have to take precautions before things get worse. There are tons of other diseases also but these are the common diseases which I’ve mentioned in the chart. Don’t be casual at that time if you notice these types of symptoms on the fish’s body. Otherwise fish will die soon under rocks.
Over-crowding occurs in a fish tank
Overcrowding is one of the main issues why your fish is hiding all the time under the rocks in the aquarium. Lots of new aquarists don’t know what will be the proper places for each of fish. They put lots of fish in one aquarium to make it visually beautiful but ultimately after a while weak fishes start hiding under rocks.
If you are noticing something like that then you need to consider this issue as a possible reason of it. At that moment weaker fishes feel unsafe and start to find a safer place. So they start hiding.
I can’t tell you what space your fish should need to stay active because I don’t know what fish you have in your fish tank. But here I can give you some general overview about the free space of different types of fish that need to be active all the time. So let’s take a look
| Fish Species Name | Tank Size | Remarks |
| 1. Kissing Gourami | 50 gallons | Per pair |
| 2. Albino Rainbow Shark | 50 gallons | 125 gallon for more than two |
| 3. Neon Tetra | 10 gallons | 10 gallon for group |
| 4. Molly Fish | 10 gallons | Most Recommended 30 gallon |
| 5. Swordtail | 15 gallons | One fish need 5-6 gallon of water |
| 6. Tiger Botia | 75 gallons | 150 gallon for fully grown fish |
| 7. Butterfly Fish | 75 gallons | 150 gallon is enough for all species |
| 8. Killfish | 20 gallons | Per pair |
| 9. Goldfish | 20 gallons | More space means more healthy |
| 10. Harleyquin Rasbora | 10 gallons | Pair per gallon |
| 11. Cichlids | 30 gallons | Safest option 50 gallon |
| 12. Boesemani Rainbowfish | 30 gallons | For 6 number of fish |
| 13. Guppy | 10 gallons | One fish needs 2 gallon of water |
| 14. Clown loach | 30 gallons | 150 gallon is needed for adults |
| 15. Discus Fish | 50 gallons | 7 gallon is ideal |
The remarks section is the most important section of this chart. Here I’ve told you what the most important thing to remember while putting fish in an aquarium is. Some fishes love to stay alone. If you are a beginner then you should not go for those types of fish. Start with some school fishes and these will not hide if you do other things well.
During the Hatching times of eggs
When it is time to give birth some fishes try to hide for some days because during this period of time they can’t able to fight back if they are attacked anyhow. So the safest option available for them is to hide under the rocks or anywhere else in the aquarium.
So you need to prepare some safe spots for them if you are planning to hatch them. You can make some caves with some driftwood or you can use some aquatic plants also to make some hiding spots.
Another possible sign is that they will not take much food at this period of time. So if your fish is hiding and not taking any food then there is a strong possibility that they are pregnant.
Final thoughts
Hiding is not bad for fish. Sometimes when it wants to explore its home then it may hide. So if your fish is hiding sometimes then you don’t need to worry much. But if this thing happens frequently then you need to check these possible causes which I’ve discussed in this article.
You should check the water parameter must. Lots of new aquarists skip this and think that it is wrong inside the fish. If it is wrong inside the water then you can’t even see through your bare eyes. That’s why you need some tools to check this. But if you see one of these causes then try to fix it as soon as possible. Otherwise, things will be worse.
So best of luck & happy fishkeeping 🐟