Why Are My Pond Fish Hiding? (And How to Fix it)

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Why are my Pond Fish Hiding? Guide to Koi Shyness & Solutions (updated)

koi hiding
One of the best aspects of a garden pond is seeing your fish, so having fish hide can be quite frustrating.

One of the most frustrating problems with a fish pond is not being able to ever see the actual fish! Fish that hide all day can make a garden pond seem empty and lifeless, especially when they’re supposed to be the main attraction. Although this is often a common problem with newly introduced fish, it can also be a problem with older fish who have been a part of your family for a long time.

There are numerous reasons why koi and goldfish may become skittish or go into hiding, and it can be difficult to determine the exact cause. The reason could be a single issue, such as a shyness in a new environment, or a combination of many issues making an older fish stressed and skittish. Luckily, for most common causes, there are things you can do to help re-build confidence and give them a friendly nudge out from hiding.

Are koi more skittish than goldfish?

Both goldfish and koi can demonstrate skittish behavior, although we find that koi are more susceptible to a sudden change in behavior even when they have been comfortable for a long time. This is because koi are more sensitive to changes in environment than goldfish, and may become stressed or frightened under certain conditions. For example, a changing water pH or rising ammonia level in the water will likely start to affect koi sooner than goldfish, so you’ll notice a change in behavior first in your koi.

Sometimes fish also just need some “downtime” to de-stress, and they should start to acting normally again after a short period of hiding away. This applies to both koi and goldfish, and should not be a problem unless the behavior continues for more than a few weeks.

If there is a sudden change in behavior or things just aren’t getting better after along period,  you may need to take a closer look at your pond to try to determine if there is a problem present.


Common Reasons Koi or Goldfish Hide

1) Newly Introduced Fish

It’s not uncommon for new fish to turn down food and hide for a few days before they build confidence.

Probably the single most common reason for fish to start hiding is if they’re newly introduced to a pond and haven’t had time to get used to their new environment. This can happen in both brand new ponds after adding multiple fish, or when you add a single new fish to a mature pond alongside your older fish. In both cases the fish have just had a huge change in environment, and this can be quite traumatic to both koi and goldfish. After adding a new fish to your pond, it’s actually very common for them to hide and act shyly for a few days while they slowly begin to explore their surroundings. This hiding behavior should not be considered a problem unless it continues for more than a few weeks, or you notice the fish is not eating any feed you provide. Even if the fish doesn’t eat with you close, it will likely begin eating when you retreat to a further distance from the water. Typically new fish shyness resolves on its own in time, so is not usually something to worry about.

2) Predator Attacks

Another common and more serious problem which may be affecting your fish and causing them to hide is attacks from predators, such as herons. Even if you don’t notice any predators in your garden, this doesn’t mean they’re not paying your fish a daily visit! Herons, for example, usually visit ponds during the early hours of the morning or right before dusk, so unless you’re around during these times you may just be missing the action. Telltale signs of predator attacks on fish are missing fish, damaged scales, injured fins, and fish that are constantly hiding. During an attack fish will instinctively retreat to the deepest point of the pond for shelter, and they may remain there longer and longer each time unless the threat is removed. Predators will also cause stress for pond fish, which over time, may start to affect their general behavior and confidence.

3) Changes in Water Quality (pH/Ammonia)

Maintaining good, stable water quality is one of the primary goals of fish keeping, and a change which affects the overall balance can cause fish to act strangely or even become sick. The term “water quality” refers to a number of different layers which make up healthy pond water, with the most important being pH, ammonia, nitrite, KH, and GH. For pond fish, and in particular koi, keeping these levels stable and within a safe range is very important for fish health. A sudden swing in pH, or a rise in ammonia, for example, can cause huge stress on fish and force them into hiding. Testing water annually or at the sign of problems (hiding fish) is good practice, as an imbalance in substances could easily be a factor for newly skittish behavior. Rapid changes in pH and a spike in ammonia are often the most common culprits in these cases.

4) Poor Quality Fish Food

One of the best times to say hello to your fish is during feeding sessions, and in most cases your fish would agree! However, if you’re feeding koi or goldfish a low quality fish feed they may slowly become less interested over time. This is especially true in mature ponds with heavy planted environments, as fish likely have a more nutritious source of food from insects and plants. Selecting a food which meets your fishes requirements is important, as well as making sure the primary protein source is aquatic based. Many low quality feeds will have a primary plant based protein source to lower costs, as well as other “filler contents”, and sometimes fish just aren’t fussy unless it’s the real thing!

5) Sickness or Parasites

Strange fish behavior or a newly skittish fish may have a problem with parasites or a bacterial infection. A fish that feels under the weather will naturally separate itself from the group and seek shelter in a quiet part of the pond, away from everything going on. They may start refusing food, and spend more time hidden away from other fish. If you notice this kind of behavior, your fish may have a growing infection or parasite problem which may require treatment.

6) Stagnant Pond Water

If your pond is stagnant without good water flow, your fish could be suffering from low oxygenation. Pond fish require large amounts of dissolved oxygen to breath, and may become sluggish and unresponsive to food in water with low levels. As well as this, beneficial bacteria need oxygen to break down harmful substances, such as ammonia, and cannot function efficiently without it. This could lead to rising ammonia which may also be stressing your fish. If your pond has no water features, a weak pump, and you notice algae growth is rapid, you likely have insufficient aeration.


Steps to Make Fish More Confident

Step 1: Add Fish Shelters 

Fish shelters work to deter predators and give new fish a place to build confidence.

For newly introduced fish there is little you can do to prevent them from hiding until they grow used to their new environment. Generally this behavior will only last a few days, but can be prolonged if the fish is constantly stressed and has no “safe space” to retreat to. Funnily enough, one of the better ways for a new fish to grow in confidence is to make sure they have a place to hide!

If a new koi or goldfish has no where to de-stress after a sudden move, it will just take them even longer to adjust to their new pond. Providing plenty of hiding spots and shelter for fish to relax is a good way to speed up the transitional period. A fish which feels safer and more relaxed in a new pond will be more quick to adjust and gain confidence, even if that means hiding for a few days.

Heavily planted ponds should provide a good amount of natural coverage, so you likely just need to give your fish time to get used to their new home. Ponds without natural coverage may benefit from the addition of a man-made fish shelter. These are designed to provide a safe hiding place for fish, allowing them to escape predators and to de-stress when needed. They will also likely become a new fish’s best friend for the first few days they’re introduced, and you’ll often see them in the shelter while they get used to everything. We highly recommend them for open ponds with little natural hiding spots or coverage.


Step 2: Implement Predator Deterrents

There are many methods of predator control for ponds, with automatic “scarers” being a popular choice.

Predator attacks from herons, hawks, cats, or raccoons can have a serious and long-lasting effect on pond fish. If a predator is hunting fish daily, they will become less and less confident in their own pond and will start retreating to deeper water for extended periods. They may also become more weary of humans and other animals around the water, and try to avoid swimming close to the surface.

The best way to prevent predators is with deterrents designed to scare away the animals before they have a chance to catch your fish. Most deterrents are aimed towards stopping herons, but they will also work for other predators by making the garden and pond less inviting. Popular deterrents include decoys, netting, shelters, fencing, and automatic water and sound devices. Depending on how confident the predator is in your garden, you may be able to scare them with just a single method or you may need to implement a range of different approaches. The most effective in our experience are a combination of pond netting, fish shelters, and automatic “scarer” devices. Having all of these deterrents at once will stop all but the most stubborn of predators, but you can try one method at a time to see what works.

Check here for our full guide on heron and predator deterrent methods and what we consider the best choices for ponds.


Step 3: Test and Improve Water Quality

Water test kits are useful for testing water quality and can provide a range of different measurements.

Rapid changes in water quality or a gradual imbalance can cause fish to become stressed, sick, and go into hiding. Testing water quality at the first signs of problems will help you determine if the cause is related to your ponds water chemistry. Common culprits are a high or low water pH, and a rise in ammonia levels. Both of these measurements, and more, can be calculated using a water testing kit or an electronic pH reader. These tools can provide accurate readings for a range of water measurements, allowing you to determine if your pond is within safe parameters for fish keeping. If your pond is having problems with ammonia or pH it can usually be resolved before too much harm comes to fish, although the most important thing is to make sure everything is as stable as possible! Sudden swings are much more dangerous than gradual changes, even when trying to fix a problem. It’s better to maintain a more stable environment and slowly improve things than to try to adjust water quality quickly with a “quick fix” treatment.

For more information on the ideal water measurements and how to test them, check our guide on testing pond water here.


Step 4: Try a Different Fish Food

A more tasty and nutritious food source may be all a fish needs to come out of hiding.

Fish may start turning down food which is low quality or has too much filler content, and you may mistake this behavior as the fish hiding from you. In a matured pond fish have plenty of natural food sources, so unless the food you’re giving them is particularly tasty, they may start turning it down more often. Feeding time is a good way to get better acquainted with your fish and build a strong and confident relationship. Pond fish who love their food will also love you for providing it, and they’re unlikely to stay hidden long when it’s dinner time. It’s important to interact with your fish daily during feeding as this is the single best way to gain their confidence and reduce hiding if they’re scared of you.

If you notice your fish aren’t taking as much food as usual when you’re actively feeding, or turning down food altogether, we recommend switching up their feed. A fish food with a high quality aquatic protein source is preferred as this is a more natural diet, and most fish prefer it over plant proteins. In general, a quality fish feed should be 30% protein, 3-12% fat, and have minimal ash (filler) content. This range will provide optimal benefits for growth and strong immune systems, with as little waste as possible.

For recommendations on quality koi foods and more information about the ingredients, check our article here.


Step 5: Treat for Parasites and Infections

Sick fish will usually hide and prefer to be alone, but any infections can be solved with treatments.

A sick fish will instinctively break away from the group and try to find shelter elsewhere in a secluded part of the pond. Fish with parasites or infections may start acting strangely, often sluggishly, and become very uninterested with food.

If you notice a sudden change in behavior which is accompanied by your fish hiding regularly, you can treat them for both infections and parasites to be on the safe side. Common parasites, including flukes and tapeworms, can be treated safely with Aqua Meds Prazi treatment. Bacterial infections can be remedied with a wide-range treatment which helps improve the fishes immune system and promotes recovery. We recommend API Pond MELAFIX for both new and mature fish to treat infections such as eye cloud, fungus, and fin/tail rot.

Treating for infections and parasites is a big part of fish keeping, and is usually something pond owners will perform every winter and spring for optimal health. These kinds of treatments also work well after a predator attack to help improve recovery and prevent open wounds becoming infected. Most treatments contain natural active ingredients and will not harm or stress your fish, so you can use them safely on a regular basis if needed.


Step 6: Improve Aeration and Filtration

Activated carbon can help remove harmful substances and improve water quality.

Stagnant water with low oxygen content or a poorly filtered pond makes for very unhappy pond fish! If fish are hiding or don’t want to know, it could be that they’re trying to tell you something is wrong with the water. Both goldfish and koi need plenty of oxygen to thrive, and will become slow and even sick when levels get to low. Oxygen is also needed for beneficial bacteria to break down harmful substances before they can build up and become a danger to  fish.

As well as this, ponds need a good filtration system, and sometimes the eco-system can be improved simply with better filter  media or additional bacteria to supplement the process. If you have many fish in your pond, you should also ensure your filter box is large for effective filtration. As a general rule, you cannot ‘over filter’ a pond, so the bigger the better in terms of fish keeping!

If your pond has little aeration, you can consider adding a water feature or an air pump which will add both flow and oxygen to the pond. To improve filtration, you can try optimizing your filter media, adding activated carbon to remove chemicals, or supplementing with more beneficial bacteria.

21 thoughts on “Why Are My Pond Fish Hiding? (And How to Fix it)”

  1. We were broken hearted when our five beloved goldfish disappeared. A “mating” box turtle invited himself into our goldfish pond, and he persistently swam there daily for one week. At that time, our fish completely disappeared. We searched under pond plants and rocks to no avail, and so we assumed the turtle ate them.
    For an entire month afterward, we mourned our beautiful “goldies.”
    Suddenly they reappeared, … there was no obvious explanation. We are sure they are the same individuals because of their spots and mature sizes. We feel like a miracle has occurred!
    HOW OR WHY DOES THIS HAPPEN?

    • Hi Sally,

      I’m so happy to hear your goldies returned! That must have been very stressful not knowing.

      Fish, even larger species like goldfish, are still prey animals and will have a natural instinct to retreat if they feel threatened. The arrival of the turtle likely spooked them enough for their instinct to kick-in and cause them to lay-low until they grew accustomed to the change in their environment. If their sizes and colors are still good, it means they were eating well while hiding (likely plants/foliage/critters), so I’d consider that lucky!

      Have you considered added some artificial fish shelters to your pond (also called “koi castles”)? These can be useful for providing fish a singular and safe hiding spot, and as a bonus, at least you’ll know where they all if something similar happens in future!

  2. My 3 week Koi will not eat on the surface. Also, they will not swim when I am around the pond. I don’t know if they eat any of the food.

    • Hi Julia,

      Koi, especially juveniles, can take a long time to grow accustomed to a new environment, and it’s not unusual for them to hide away frequently during this transition period. In most cases, koi will eventually get used to their new home and slowly become more confident, but others have more skittish personalities and it can take extra work to get them happy feeding with people around. The best thing you can do in these kind of situations to encourage them is:- 1) ensure water quality is good, 2) ensure your feeding routine is regular, and 3) ensure you’re feeding a high quality (tasty) koi food.

      If all the above is checked-off, and they still they won’t feed with you close-by, you can try throwing the feed a short distance and then crouching down away from the pond edge. This will reduce your shadow on the water, and they will be more likely to start feeding closer to the surface. If they begin feeding with this approach, slowly begin moving closer and closer every few days, watching their behaviour and adjusting distance accordingly.

      Once they realise you’re the person who provides the tasty food every day, they will eventually come and greet you instead of hiding when you’re around. This process can take a long time depending on the personality of each fish, but if you keep working at it every day, you will eventually start seeing results!

  3. I have had my current Koi and Comets for 3 years now. The comets have had babies twice. They have always been skittish but were pretty friendly at the beginning of this year. Once summer came they started hiding under my lilly and floating plants again. They come out quickly when I feed them but wont stay out if I hand aroud

    • Hi John,

      Do you have any predators in the area? Possibly herons, or neighbouring cats?

      If this behaviour has started recently, you could have a predator stalking the pond in your absence, which may cause the fish to hide for protection when they notice a shadow on the water.

  4. Hi, today as i went out to feed my fish i noticed that my only koi had gone missing. i have 8 other gold fish as they are all accounted for, even the large ones. my koi has been with me for a while now, maybe 3-4 months and she usually comes out to eat when i feed my fish, but today she was no where to be seen. i do have some neighboring cats and stray animals around my area and when they have gotten to my fish they usually just play with them and leave their bodies behind. any idea on where my fish got to?

    • Hi Olivia,

      Do you have any pond netting in place? If so, did you notice any damage or disturbance to the netting? Also, how big is this pond? Can you see all hiding areas?

      My guess would be a predatory bird, such as a heron, but it could also have been a cat (or even raccoon), especially if your koi was quite trusting and often came to the surface for food.

      I do hope you koi turns up, but in case she doesn’t, I created an article here on some good heron/predator deterrents that may help in future: https://pondinformer.com/best-heron-deterrent-ponds/

    • Hi Chris,

      Congrats on the new pond!

      Yes, that is pretty normal behaviour. It usually takes some time for fish to acclimatize to their new environment, especially if they’re not used to your particular water parameters (e.g., a change from soft to hard water, and vice-versa).

      On the other hand, it could also be some underlying problem with water quality. Have you performed any water quality tests on this new pond? If you have performed testing and the results are coming back all clear, I’d be confident to say your new fish probably just need a little more time to get comfortable. Although it’s difficult to predict when this will happen, you can often speed up this process by making sure water quality is good, pond maintenance is carried out, and they’re being fed a good quality food.

  5. I have a 7 x 9‘ pond in my front yard, I have had it for several years and the fgoldfish have reproduce quite often took 50 out earlier this year and put in a bigger pond. Had about 40 left now I only see three. The water is clear pump seems to be working fine but haven’t seen any fish. I did see the ones left for a week or so afterwards. Have moved the water plants and the pump in the pond but didn’t stare up any fish.

    This is never happened before. Don’t know what happened to my fish.
    Wasn’t Too concerned at first because the weather has been cold and then warm again.

    • Hi Lois,

      It’s very strange for that many fish to vanish so suddenly, so I’m inclined to say they’re not just hiding away somewhere. Have you ever had any problems with predators in your garden before? For example, I know from personal experience that a single heron will be able to devour a whole pond of small goldfish in a few hours if given the opportunity. The fact that your water is so clear just makes the fish even easier prey, especially without any nets, fences or deterrents in place. If your goldies don’t turn up soon, I’d suggest having a look through the below articles for further advise on common predators and solutions:

      https://pondinformer.com/pond-fish-predator-guide/
      https://pondinformer.com/best-heron-deterrent-ponds/

  6. I introduced 2 baby Koi about an inch long or so to my pond before the winter. They swam around for about two minutes and then never came out of hiding in the rocks that surround the pond. My larger koi that looks most similar to the Koi I bought probably about 18 inches long has been
    staring obsessively looking into the rocks for the better part of nine months and I believe there still alive. Im worried they are going to get trapped because they may be getting too big to stay in there they’ve only come out once just before winter set in for a second or two which let me know why my fish was staring inside those rocks . Would love some advice on what to do

    • Hi Karl,

      Sorry to hear you’re having problems with your new koi! That’s a difficult question to answer without seeing the pond, but I do know from experience that most fish will need time to acclimatise to a new environment, especially if there is a drastic difference in water condition coming from their stock tanks. With that said, nine months is a very long time for fish to be hiding, so it makes me feel something else if afoot here.

      The much larger koi could indeed be scaring them into submission, as koi will sometimes pick on and “bully” new fish. Given their small size, this behaviour from a much larger aggressor could certainly be keeping the smaller fish hiding away. More info on this here – https://pondinformer.com/how-to-stop-koi-bullying/

      With that said, I feel you will also need to confirm in the near future if they’re actually still alive and healthy. One way to do this safely would be to remove the larger koi and place him into a holding/stock tank temporarily while you remove the rocks and check on the little ones. If they’re well, and depending on their size, you could then re-introduce them in a controlled manner and closely monitor the behaviour. If you sense any aggression (past what could be considered a normal “pecking order”), you may need to separate either the bigger koi or the smaller fish and allow them to grow out, or simply let them go back into hiding until they’re bigger and bolder. If you find them healthy without injury, it probably means they’re getting enough food where they are and just need more time to grow into the pond.

      In any case, the first thing would definitely be to confirm if they’re still alive. 9 months is a long time to not even see a glimpse of them!

  7. I have a small pond 6x8ft and it’s been fine until my older Goldfish started dying off they were from a funfair years ago , my son is now 30!! So they had a good life . I replaced them with four golden English Koi , I think they were called, they were very shy and hid all the winter , then started hanging about with the oldies , but they all stay in the bottom of the pond . They eat after I’ve gone . I have a pump , filter box and uv filter going . The water check says all is well . The pump runs a waterfall and there is a solar fountain . It has a shallow end and planting , but I still never see them come up . Whilst on holiday two oldies past away , one with severe swim bladder that he’s mastered over the winter , and one that just went blind and swam around , with that the Ammonia level had gone up a tad , but a small top up levelled it again . But still no fish movement . One oldie left and four yearlings , I was thinking of adding a couple of new fish to spike their interest what do you think please .

    • Hi Suzanne,

      Sorry to hear about your recent fish loss. No matter how young or old the fish are, it’s never easy! It does sound like they had a long and healthy life though, so you must have done a great job maintaining the pond over the years!

      In terms of adding more fish, I think it may be better to give the new fish a few more months to get used to the environment before increasing stocks. Fish have different personalties, and some will just take longer to grow accustomed to their new home than others. Adding even more new fish before they start to feel “at home” may just slow this process down more, so I’d definitely say give it a little more time. If the new fish are not very interested in feeding, you could try switching to a different feed and see if it helps entice them out – https://pondinformer.com/best-koi-food/

      Also, how sure are you that these new fish are koi? Golden Orfe can look similar when they’re young, but have slightly different requirements for optimal health, so it may be worth double-checking if you can. More info – https://pondinformer.com/golden-orfe-pond-guide/

  8. Hi, my fish have not been seen for about a month. I know they are there because they are eating. I have lilies in my pond and weeds for oxygen.
    Can you give me some advise please.
    My pond is well established, had it for over 2 years.
    Thank you.
    Barbara.

    • Hi Barbara,

      How were your fish acting previously? They could be stressed or ill, so you may want to try using a net to catch them and then place them in quarantine tanks to observe them. Or, it could just be that a new predator is around. Have you noticed any foxes, raccoons, hawks, etc. nearby? Perhaps your fish are simply trying to keep hidden.

      Depending on where you live, it could also be related to the change of the seasons. As things cool down, many fish will, much like us, naturally become a bit more sedentary and prefer to hide out more often than usual.

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