There are many reasons why pond fish get stressed, this can be something simple like a sudden change in the water temperature to insecurity, in this article we will look at the causes and solutions of fish stress.
We all get stressed at times and it’s no different for fish, you wouldn’t think you fish would get stressed, why would they, all they do is swim around in your beautiful pond all day and get feed on a daily basis, sounds like an idyllic life, but there are lots of things that can stress you fish.
Water temperature: pond water fluctuates through the year, but a sudden change of water temperature can bring on stress in your fish.
Fish are cold-blooded and can usually adapt to a wide range of temperatures but if that change is sudden they can get stressed.
This is why you always need to acclimatise new fish before you add them to your pond.
During the summer months the water in your pond can shoot up in temperature, especially if it’s a shallow pond.
You can slow down the speed your pond heats up by using shade, surface plants like lilies are ideal, they provide shade for your fish and keep the temperature from rising too quickly.
If you need to top up your pond during the summer months make sure you do it slowly, filling up your pond quickly with cold water will shock your fish.
Water quality: poor water quality is a major factor why your fish might be stressed, the funny thing is it’s usually caused by the fish themselves.
They produce waste (poo) which they do straight in to the water they swim in, they don’t have fish toilets, I think I would get stressed out if I had to swim in my own waste.
It’s not just your fishes waste that effects the water quality, rotting plants and uneaten fish food also contribute.
All this breaks down and releases toxic chemicals into your ponds water, a good filtration system will usually remove the toxins, but if you think your fish are stressed do a water test.
Water pollutants: this is related to water quality but rather than toxins being produced within your pond this is chemicals that can get into pond water from other sources.
We are talking about things like tap water which has chlorine or chloramines added which you might use to top up your pond.
Fertilisers that you put on your lawn and pesticides you spray on your plants, these can be blown or washed into your pond.
pH levels: ideally pH levels should be as stable as possible, unfortunately they fluctuate from time to time.
If they change by more than 1.0 it can really stress your fish, also high levels over pH 8.5 and low levels under pH 6.5 will cause stress.
Oxygen: it sounds strange to include oxygen in this article, but I think I would get stressed if my supply of oxygen was limited.
Fish rely on dissolved oxygen, bad water circulation, organic waste and water temperatures can reduce the amount of oxygen in your pond.
It’s at night when pond plants deplete the oxygen that fish get most stressed, but if it’s bad they can suffer at any time.
Physical stress: when we talk about physical stress we are talking bodily harm, this could be from rough handling of your fish, predators attacking your fish or simply your fish injuring itself on rocks in your pond.
Overcrowding: if like me you hate overcrowding, I know it makes me stressed, but at least I get out of there to avoid all the crowds, your fish have no option.
They have to live in the pond you have provided, but it’s not the amount of fish that stresses your fish it’s the amount of waste they produce and the oxygen they use that will cause stress in your fish.
Diet: your fish need a well-balanced diet, but a diet that lacks nutrients can cause stressful conditions for your fish.
Insecurity: this is how your fish feel in your pond, if your pond is nice and clear it’s great for you, you can see your fish swimming around, but your fish will feel insecure because they are not happy with their surroundings.
If your water is clear and there is no hiding place or surface cover such as lilies for your fish to hide your fish will feel vulnerable to attacks from predators, especially if they have already been visited by a predator in the past.
Infection: this is like catch twenty-two, your fish gets stressed which might lead to an infection, if they get an infection they get more stressed which leads to more infections.
Can you tell if your fish are stressed
There are ways you can tell if your fish are stressed, you need to watch your fish to see if they have any of these symptoms.
Gasping: if your fish are gasping for air on the surface of your pond it’s a sign that they are stressed because of poor water quality and a lack of oxygen.
Hiding: if your fish are staying on the bottom of your pond or hiding under waterfalls or ledges it could be stress related, also keeping to themselves and not feeding with the other fish is another sign to look out for.
Swimming: another thing to look at is how they are swimming, are they lethargic or swimming rapidly, are they swimming against things in your pond as if they are trying to itch themselves, any of these might be a sign of stress.
Disease: check you fish for disease, this can stress your fish out, also while your at it check for sores or other visible ailments.
Feeding: is your fish eating, has it got a good apatite, a fish that is stressed often looses it apatite and will often not eat at all.
Floating: is your fish lying on its side or partially laying on its side.
Can you calm a stressed fish
Yes there are things you can do to reduce the stress in fish
Water: the first thing we would suggest is to test the quality of the water in your pond, there are plenty of test kits available to do this and you will find out if there are any issues.
Even a small change in water quality can affect your fish so check the pH levels, nitrates and nitrite levels and ammonia levels, if you find the levels are outside the safe range you will need to treat or clean your pond.
Infections: another thing to look out for is infections, injury, discolourations and parasites, if any of these are found your fish will be stressed and you will need to treat your fish accordingly.
Predators: if you think your fish are stressed because they are worried about predators attacking your pond use measures to keep the predators at bay, we have an article about herons that might help you, you can also add hiding places within your pond.
Oxygen: getting more oxygen into your pond through aeration will keep your fish stress free and help beneficial bacteria break down all the waste in your pond. You can use air pumps, fountains and waterfalls, adding plants will also add oxygen to the water.
Overcrowding: if your pond has to many fish you should think about removing some, if this is not an option you will need to upgrade your pump and filter system to one that can cope with the amount of fish you have.
Treatments: there are products you can buy that can reduce fish stress, like this API stress coat from Amazon they add a protective coat around your fish which will help them heal and it makes tap water safe.
Can stress cause a fish to die
Unfortunately stress can cause a fish to die which is why you should do everything you can to provide a safe, clean environment for them to live and if you find a stressed fish you should treat the problem or the fish to give them the best chance you can to avoid its death.