The Beast Gets Sunburn

Something is wrong with The Beast. My peachy-white eleven-year old koi has what looks like red gashes on her sides and head.

koi head sunburned


Looking closely, I can see that she isn’t wounded, nor has she rubbed herself raw (as fish sometimes do when irritated by parasites.) I Googled a description of her symptoms, and discovered, much to my surprise, that koi get sunburned! Pale-skinned koi, like The Beast, are especially susceptible.

Why was this the first year that I’ve seen such sun damage? I think it’s because The Beast is now enormous. Lily pads that used to shade her, are now like small polka dots overhead.

small lilies


In the late afternoon, bright sun reaches deep into her cave, but she is now too big to lurk in its dark recesses.



My Google search taught me that pond salt helps to  promote slime on a fish’s scales, which acts as a salve for sunburn. I bought a carton. It’s a big pond. I poured the entire contents around the perimeter.

pond salt


I bought another waterlily. This one has especially large pads.

new lily


It’ll take awhile for the waterlily to grow more leaves that will provide enough shade to prevent sunburn on the koi. In the meanwhile, I’ve moved the umbrella away from my chairs, over to the edge of the pond.



I don’t mind. I can wear a hat. Which is not something that I can see putting on The Beast.

sunburned koi


  1. Goodness, she IS big. (She? How can you tell?). Clever you for figuring this out.

    • I’ve read up on koi behavior, and the way the other fish follow her and how she reacts to them, makes me think that the Beast is female.

  2. Terry, she is a big one and your pond is beautiful! Are all the small fish her babies or just a different kind of fish?

  3. A number of years ago I put a few plain goldfish into the pond with the Beast. What you see are their offspring. Some with each other, some with her.

  4. Well I never knew koi could get sunburn! Looks like you’ve done all you can to help protect her Terry, although I would like to have seen the ‘Applying suncream to Koi’ article more!

  5. Who would have thought about fish getting sunburned? We hope the addition of salt and shade will make The Beast comfortable.

  6. I am amazed at how clear your pond is, especially with all those fish! Maybe a murky pond is the answer to preventing sunburn on our gilled friends?

    • I don’t add any chemicals to the pond to keep it clear. The water filters through 4 feet of gravel and water celery roots (that’s at the back of that big rock) and the fish eat the algae. I think that murky has its own issues :)

  7. We had Koi when we lived in Manhattan Beach before we moved to Cambria and had one like the Beast. He got something that looked a lot like what the Beast has and it was a fungus. We put him in a kiddie pool with some medication for about an hour and then he was fine. We consulted our local Koi dealer in Gardena however before we did that.
    The best to the beast.

  8. I’ve heard of people floating styrofoam sheets or boards hooked together for temporary shade as well. You might want to consider a permanent fixture shade option other than the lilies. I hear they can get burned in winter as well. Who knew? (A friend of my daughter’s in high school was raising show koi. Who knew fish could cost so much?)

    Also, if your guesstimate on the salt doesn’t appear to be helping, fish are easily trained to come to you and be picked up or netted. (I’ve even trained them to sit quietly in my hand so kids could see them up close.) You can then give the Beast a salt bath in a known concentrate. 1 tlbs./gallon of water is good. Do not use table salt. It has anti-caking additives. And use water from the pond. You can leave him in the bath for up to 10 minutes, but watch him the whole time. Some fish can’t tolerate the salt for long periods and lose their equilibrium and roll over. At that point remove the fish immediately back to fresh water. As awful as that may sound, salt is actually both good for the fish and a safe medical treatment. You can treat them twice a day.

    Fungus has been known to attack fish with damaged skin so keep an eye out for that. Nasty stuff.

        • Pick your poison, so to speak. :D I haven’t personally trained pond fish, but in observation, the only difference I’ve noticed between pond and tank is time (and patience) at the beginning. The pond fish are less of a captive audience, so to speak. Oh, and they’re bigger to handle – two hands needed! :)

          I’ve used a variety / combinations just depending on the circumstances and the breed of fish. Goldfish/Koi do well with voice and visual. They are -very- interactive fish. I like to use voice and a distinctive treat container. The sight of the treat container can help on a day their attention is lacking and you really need them to get a move on. Or away.

          Treats are whatever works with that fish. Worms in all their varieties are generally a favorite. Even freeze dried tubifex worms (they come in cubes). Goldfish/Koi are generally not picky. Even just extra ‘regular’ food works. In the beginning, when you’ll be doing a lot of work with the Beast, from a dietary perspective, it’s a good idea to use regular food. Use a different variety or flavor. You can also spike some pellets by letting them soak a bit in something ‘smelly’. Like maybe some defrosted blood worms/juice. Of course, those would need refrigerated if you didn’t use them all. I’ve heard chopped up earthworms are good, too, to spike the pellets. But I’m too much of a wuss to chop them myself. (Yeah, yeah, I know. I’ll feed them to the fish, but I can’t chop them up, what’s the difference…

          As a teenager I got interested in training fish (realized they weren’t the dummies everyone said they were) when I realized they could tell which food they were going to get by the container markings. And these were just tropicals – guppies, barbs, danios, etc. In the Big City at the Zoo, the aquarium keeper has the sharks trained to lie quietly for exams and blood draws and sharks are not the sharpest tools in the shed. The Goldfish family is one of the smart ones. They can even learn their names. Once the Beast learns there are extra goodies to be had spending time with you, you may truly wind up with a ‘Beast’! :D

          • Oh, a quick add on after chatting with my daughter. I just said ‘voice’ above but sound will work. It will need to be loud enough to be heard in the depths. I’m not sure if your clicker will be enough. But I, personally, don’t know anyone who has tried it. It might if your pond is small enough. The objects I’ve seen used to bring the fish in for feeding at ponds – one of those old dinner triangles hung at the edge of the pond :), one person banged a stick three times on a specific rock on the edge of the pond, and someone else shook a can with rocks in it. Voice is more popular. -Though- the people who spent time with and around their fish only needed to show up at the pond to bring everyone in.

            • Robin, this is just what I needed from you! The Beast has only been fed koi pellets from me, so something special will really make her… maybe truly … “leap for joy!”

  9. Whodathunkit? And such a knowledgeable group of responses, too. Fascinating post. Hope she is sorted out soon.

  10. I wouldn’t have guessed fish could get sun burn. I used the umbrella idea for shade and rain shelter for my chicken run before building in something more permanent. It’s a good instant temporary measure for a small area of relief. Only problem with chickens is it took days before they would pass under it and then when used it to it they wouldn’t go near it when it was down (on good days). Eventually we moved on to panels that can slide open and shut as needed but for a while the umbrella gave a patch of dry shade. I love a bit of improvisation. Good for you for spotting the problem and dealing with it. Long live the beast.

  11. We have a pond and garden shop on the opposite coast, where we sell koi and work with koi keepers on their pond and fish health issues. We are not vets! But, may I recommend dosing salt at 3lb per 100 gallons of pond water, divided into 3 separate applications. Under dosing is a bit like using antibiotics on a whenever basis; parasites become more resistant if not knocked back by the salt. While it looks like sunburn to me, one is cautious about controlling parasites/ bacterial issues that may attack the injured flesh. Salt, though, can damage pond plants. Just be aware if they appear to suffer. TheraP by Microbelift can help with immune boosting. Also, you could toss in a few water hyacinths. They spread readily, but are annuals in our respective climates and won’t invade (good compost at end of season). They would make good, quick shade for Beast and buddies. Thank you for your blog and wisdom– one day I’ll get up the nerve to keep fowl; at the moment I keep only fish!

    • Good advice! Our pond is large and irregularly shaped. We can only guess at the gallons it holds. Is it better to err on the side of caution? I’ll go purchase some hyacinths.

      • Yes, I’d say so… Unless you have an interest in creative geometry and can add together measurements of somewhat more regularly shaped sections. L x W x D x 7.5 will give rough gallon estimate.

  12. Remember that student that drew a picture of the beast and she DID have a hat on? A top hat I believe!!!! LOL!