Goldfish Disease Symptoms: 14 Early Signs that Your Goldfish Are Sick

Image of Goldfish Disease Symptoms
Photo by Ajari (Flickr)

There are a lot of responses to this article – I’m very happy to have helped so many sick goldfish. If you notice goldfish disease symptoms and need help, please scan the comments/replies already made before writing a new comment or email. Your question might be already answered!

This is the first part in the goldfish disease series. In this three-part series, you’ll learn…

  1. How to tell if your goldfish is sick (we’ll look at 14 goldfish disease symptoms)
  2. How to treat 7 of the most common goldfish diseases in aquariums and freshwater ponds
  3. How to keep your aquarium completely disease free by solving common tank problems

Goldfish are remarkably hardy creatures and don’t often fall prey to goldfish diseases. You just need to maintain good water quality, keep up with tank maintenance, feed your goldfish a varied diet, and test the water regularly. In fact, chances that you’ll find goldfish disease symptoms are slim if your goldfish are kept in a healthy aquarium environment with proper goldfish care.

You may be surprised to find out that most experienced aquarists have very little experience treating fish diseases. This is because they are experts at keeping their fish healthy. – David E. Boruchowitz, author of Aquarium Care of Goldfish

But even under the best conditions, goldfish aren’t entirely immune to diseases.

When you have sick goldfish, you want to catch goldfish disease symptoms early on to prevent goldfish diseases from spreading and infecting other fish in the aquarium.

Some infections are even fatal and can quickly kill your goldfish in a matter of days. This makes it even more important to have a medication like this on hand and treat goldfish disease symptoms quickly.

Treat Sick Goldfish Early

There are two types of goldfish diseases: those that are contagious and those that aren’t. Even if the infection isn’t contagious, you should still put your goldfish in a “hospital tank,” a smaller tank separated from the other fish, so that your goldfish can recuperate without being stressed out. Separating the infected goldfish prevents your healthy fish from receiving medication they don’t need (what is called being “over-medicated”).

First, we’ll look at abnormal behavior signs that could hint that something’s not quite right in the aquarium. Next, we’ll dive into the visual signs of diseases on the body and fins. Later, I’ll walk you through your next steps after you’ve discovered potential problems.

Let’s take a look at a few goldfish disease symptoms to look out for. If you notice any of these symptoms in your own aquarium, it might help to write them down on a notepad to make it easier later when you’re ready to determine what caused the goldfish disease and how to treat your sick goldfish.

Goldfish Disease Symptoms in Behavior

  • Gasping for breath, rapidly breathing, or hanging at the water surface – This is one of the first signs that something is wrong. You may notice that one or more of your goldfish are gathered at the surface of the water, noisily gobbling up packets of air or sucking in oxygen just below the surface. This usually happens when the water isn’t oxygenated enough for your goldfish to breathe comfortably (poor water quality). So sick goldfish will try to find any means they can to get more oxygen. If water quality doesn’t improve, the stress of not breathing in enough oxygen will lower the immune system and cause other goldfish disease symptoms to develop.
  • Refuses to eat or losing weight – This is another goldfish disease symptom you should catch early. Goldfish are naturally ravenous creatures and will eat just about anything if given the chance. So a goldfish refusing to eat or showing noticeable signs of weight loss should be a warning sign that there’s a problem that needs closer looking into. Your goldfish might be suffering from internal parasites or poor water quality.
  • Erratically swimming or swimming upside down – Erratic swimming is a sign of buoyancy problems. Trouble swimming could be caused by swim bladder disease, dropsy, or improper feeding. Poor water quality might also be the culprit (or a result of overfeeding). If you look closely, are there other goldfish disease symptoms you may not have noticed?
  • Listless or laying at the bottom – Healthy goldfish actively swim around and interact with their environment, so if you have a sick goldfish that never gets up from the gravel, something is seriously wrong and you should take immediate action to find the underlying cause. Usually sick goldfish that are listless are also suffering from poor water quality or an infection.
  • Slow to react to disturbances and stimuli – Are you about to feed your goldfish, only to find that one of them doesn’t seem to notice the food until it’s smack against his nose? Sick goldfish often have trouble reacting to certain things in their environment. Look for other goldfish disease symptoms, test the water quality, and do an immediate water change if test results are less than ideal.
  • Rubs against the aquarium glass and other surfaces – This could be a sign of parasites, like ich, or even a fungus infection. At least, something is making your goldfish very itchy. If your goldfish is just rubbing his nose on the glass whenever you come nearby (what I like to call the “goldfish dance”), it could just be a friendly greeting and a demand to be fed (of course, don’t give in to those demands if you already fed your goldfish just moments ago). ;)

Goldfish Disease Symptoms on the Body or Fins

  • Clamped or folded fins – Maybe your goldfish constantly holds his fins close to his body or he’s lethargic and doesn’t move around much. There are actually a few potential goldfish diseases that can cause your fish to act this way, and your job is to look for other goldfish disease symptoms that might give the disease away. It might just be a case of poor water quality or parasites. Testing the water with a freshwater aquarium testing kit will give you a better idea of what is causing the problem and how to make the aquarium environment healthier for your goldfish.
  • Torn or frayed fins – This is often a sign of stress, especially if you notice little red veins branching out in the fins. Simply changing the water and separating your goldfish from more aggressive fish can quickly solve this problem. If you find that the fins are actually starting to deteriorate into a stump, your goldfish may be experiencing fin or tail rot, which is caused by bacteria (and could attract fungus infections).
  • Fluffy patches, discolored spots, or raised bumps – Do you notice a slight fuzz in some areas that shouldn’t be there? If your goldfish has discolored patches on the body or fins, chances are that he’s suffering from fungal or bacterial infections. Hospitalize the goldfish immediately and run some water tests on the main aquarium to determine what caused the goldfish disease symptoms. If the discolored patches actually look like little white specks of salt, your goldfish is suffering from ich, often known as white spot disease. Ich is fairly contagious (even common) in aquariums. If black spots are visible, your sick goldfish have an ammonia burn or parasite infection (this parasite is very rare in aquariums).
  • Bloated or has raised scales – If one of your goldfish is abnormally round, large (be careful not to mistake this for a maturing female goldfish), or even resembles a pine cone, he may have dropsy (often caused by bacterial infections and sometimes incurable). A bloated sick goldfish might also be overfed or, if your goldfish have buoyancy problems, filled with packets of air after extended periods of time gasping for breath at the water surface.
  • Pale gills – Pale gills can be caused by a number of goldfish diseases, including parasites. Salt is a popular treatment in this case, though you should also consider medications. Medications will depend on the type of parasite that is infecting your fish and can be determined by other goldfish disease symptoms.
  • Noticeable lumps or parasites – External parasites are usually visible on the body or fins, and many will cause ulcers and lumps along the scales. Such parasites include ich (white spot disease), anchor worms, fish lice, and flukes. There are many ways you can get rid of parasites, ranging from medication to salt baths. You can even have them manually removed (though I don’t recommend this unless you know what you’re doing).
  • Protruding eyes – If one or both eyes of your goldfish are abnormally large (don’t mistake this for natural characteristics in black moor or telescope goldfish), this could be early goldfish disease symptoms of dropsy, ich, or pop eye. Your goldfish could also be suffering from a bacterial infection.
  • Bleeding wounds, sores, or missing scales – Do you have aggressive or territorial fish in the same aquarium? Solving this problem could just be a matter of finding a separate tank to house your goldfish. Your goldfish could also be infected with parasites, causing him rub on gravel or other sharp objects.

By catching goldfish disease symptoms ahead of time, you can prevent infections from getting worse, spreading, and taking over the aquarium. And by taking immediate action to treat the disease, your sick goldfish has a better chance of surviving through the infection.

It’s always a good practice to watch your goldfish on a daily basis for signs of abnormal behavior or growths. A good time to do this is right before or during feeding.

Once you’ve noticed signs of a potential disease, you’ll want to put the sick goldfish into a hospital tank as soon as possible so that other fish in the same tank don’t get infected. Then you’ll need to determine what caused goldfish disease symptoms (so that you can effectively treat the disease) and identify problems running rampant in your tank (so that you can take measures to ensure your other goldfish don’t get similarly infected).

Prevent goldfish diseases with an aquarium testing kit.

Test the water with an aquarium test kit will help you identify tank problems. Also think back to events that led up to this point. Did you recently just introduce a new goldfish to the aquarium (without quarantining him first)? Did you just add new water to the tank without letting it adjust to room temperature?

Instead of looking for terrible diseases, you should concentrate on keeping your fish healthy. – David E. Boruchowitz, author of Aquarium Care of Goldfish

Remember: the best cure for any disease is prevention. By keeping your goldfish in a healthy environment, you reduce their chances of getting fatal goldfish disease symptoms. And it’s much easier to care for healthy fish than it is to treat sick goldfish.

How About You?

What sort of goldfish disease symptoms have you noticed? How did you treat your sick goldfish? Are there any goldfish care tips you can offer to help prevent infections? I’d love to hear from you!

190 Responses to “Goldfish Disease Symptoms: 14 Early Signs that Your Goldfish Are Sick”

  1. Jennifer says:

    Hi again, well my fish is still hanging in there. He’s (Tiger) has been like this for over 6 months now. I’ve stuck to my cleaning every 2 weeks or so, sometimes earlier if needed. I feed him blood worms, I guess this is supposed to help him with his possible bloat. He’s been sitting at the bottom of the tank for some time now. He moves a little. He actually moves when he sees me. Is there anything I can do? My friend told me that her fish was like this for a year before he finally died. Do you think that I should change him to a small bowl tank, with no filter? I’m just not sure what more I can do. One thing that I have noticed is, is his alge that is growing is now a reddish color. That can’t be good either. Any advice? I’ve changed water, done peas, now onto blood worms, clean tank, PH balance tested, Stress coat when I change water….. I feel I’ve done all I can. I guess he may just have to heal on his own?

    • Eva says:

      Hi guys my goldfish was kind of sick so I went to the river and got a bucket of river the nutrients and stuff made my fish better almost instantly

      • Hi Eva,

        What size aquarium do you keep (with how many goldfish?) and how were your water readings (water parameters)? Chances are, it was the addition of fresh water that made the difference (and not the river water per se). You should always change at least 25% of your aquarium water per week (treated with a water conditioner if you’re using tap water). Since goldfish are very messy fish, you should also check the ammonia in the tank. Your goldfish might have been sick from ammonia or nitrite poisoning.

    • Hi Jennifer,

      You’re sure your goldfish doesn’t have dropsy (do his scales stick up)?

      It sounds like your goldfish might have a permanent swim bladder disorder (and is struggling to maintain buoyancy). Did you also test for ammonia and nitrite? These both should be at 0ppm (parts per million).

      If the water is healthy and there’s actually something wrong with the swim bladder (a bacterial or parasite infection isn’t causing it), there’s really nothing more that you can do for him but keep him happy and well-fed (maintaining water quality). Some goldfish are born with swim bladder defects.

      If your goldfish didn’t always have swim bladder problems and there was a period of time that your goldfish was under a good deal of stress, there might be a chance that he could be suffering from a bacterial infection. If your goldfish was recently injured the months previously, he might just need time to heal.

      I hope your goldfish can get better! You can try calling the vet and ask if you can bring him in. Some vets do take fish patients.

  2. Jennifer says:

    Hello again.. so I’ve posted when my fish was sick and had his floating issues.. well it’s been months and now my fish doesn’t float he sinks… my poor fishy. I typically find him in the corner of the tank. When he sees me and I put my finger to the tank he appears to be happy.. like “hi mom!” However, I know he isn’t feeling well. I’ve reduced his feeding in a major way. I started out feeding him blood worms (heard this helps with bloat) every other day. Then I gave him a break with those and began his regular food every other day. My fellow friends have had their fish get bloat, and in the long run their fish died a year later. Can my poor fish suffer for a year???!! Please is there anything I can do? I’ve tested my water, treated my water, clean it but not too often to disturb the environment, makes sure their is proper flow of the filter. I feel as though I’ve done everything I can. I even did the feeding the veggie (pea) for a while. he honestly doesn’t swim anymore.. he is on his side scooting along grabbing food when I put it in his tank, that’s it. Is there anything I can do to make it easier to heal? Or will he just have to wait it out and see?

    • Alannah says:

      hi jennifer.
      that sounds like what our fish has been having. so far the only treatment we used was the peas. now he’s on the bottom of tank. only occaisionly moveing. what other stuff did you use to try to treat him? maybe that will help our fish.

      • Jennifer says:

        Hi Alannah, sorry it took so long for me to respond, I haven’t been on the site in some time. My fish is still having the same problem. I’m not sure now that he has “bloat” since he is a the bottom of the tank now. He’s been like this for 6 months or so maybe longer, I’ve kind of lost the time frame, but it’s been a while. When I went to the pet store, they recommended the peas, then to try blood worms. He eats them like crazy when he can get to them. He still poops and everything, which I guess is good. But I feel I’m at the end of my ropes here. I keep the tank clean, PH balanced, and all that good stuff. He gets his stress coat when I change his water as well. Really not sure what else to do. I just keep doing research but it all says the same thing, clean water, test water, peas, blood worms. I’m kind of (hands up) at this point. I don’t want my little fishy to die. I hate seeing him like that. My poor fishy baby.

  3. Linda says:

    Hello.. My gold fish is 3 years old it is so sick her tail is becoming red and its spreading and going away all over the aquarium ..its been like that for 3 days ..also its not swimming and eating and its folded its like half circle and breathing fast.. What should i do plz help me

    • Hi Linda,

      Can you tell me more about the infection? Are the fins torn or do they look like they’re being eaten away (fin rot)? How are water parameters (ammonia, pH, nitrite)?

      Without more information, it’s difficult to diagnose the problem. Your fish might be reacting to high ammonia levels in the aquarium or he could be facing a bacterial infection. Most likely, water conditions are unhealthy. In this case, I’d change 25-40% of the water depending on how bad the problem is. Test the water with a freshwater test kit if you haven’t already done so and monitor the water until conditions are healthy again. It’s also a good idea to do these tests every week to ensure water stays healthy.

      If water quality is the problem, your goldfish will likely perk right up once water conditions are safe again. Let me know if you notice the problem getting worse.

  4. Karyn says:

    My goldfish is probably about 6 yrs old now. He is very still laying on the bottom of the tank, but is breathing. There are no other fish in the tank, and I have not changed any of my habits with keeping the tank clean, filters, etc. I did just change the water too when I noticed how sick I thought he was getting. He does seem to have what I would call “blood” spots on his top, as well as near where his fins attach to the body. Is he just old and it is his time, or can I save him? He is not eating, and moves only rarely now. This is day #3 of this. I have become quite attached to the little fella. thank you.

    • Hi Karyn,

      The average lifespan of healthy goldfish is about 15 years, so your goldfish still has a lot of time left before his time. How are ammonia levels? The blood spots you’re describing sounds like it could be from ammonia poisoning. Ammonia poisoning can cause red streaks in the gills and fins, along with clamped fins (sometimes frayed) and bottom resting. If you have aggressive or territorial fish in the tank, it’s possible that your goldfish could have been injured if you don’t suspect ammonia is the problem.

      High ammonia levels can be caused by overfeeding, overcrowding, less frequent water changes, a dirty filter, or uneaten food.

      If you haven’t done so already, I recommend testing water parameters with a freshwater test kit as soon as possible. Ammonia should be at 0ppm. If it isn’t, you’ll want to do an immediate 25-45% water change depending on how bad the ammonia is. Also check for potential causes for the ammonia spike (maybe blockages in the filter need to be rinsed out with hot water or maybe you need to go through the gravel with a water siphon to remove uneaten food/waste). If the ammonia is real bad, you might want to pick up a bottle of Ammo Lock. Ammo Lock will detoxify ammonia – it won’t remove it. But it will make ammonia less harmful for your fish. There are also chemicals you can pick up to help you neutralize ammonia, but most often these aren’t needed. A good filter, some aquarium maintenance, and daily 25% water changes will usually bring ammonia back down to 0ppm as long as you fix the problem that caused the ammonia spike in the first place.

      You may even want to fast your fish for a few days until ammonia levels go back down.

      If you suspect your goldfish could have been injured by another tank mate, you might want to think about separating the fish. A little aquarium salt and clean water should help your fish heal.

      If ammonia is at 0ppm and you don’t suspect an injury from another tank mate or sharp objects in the aquarium, can you describe the blood spots you notice? If they’re tiny circular wounds, you could have a parasite infection. It’s difficult to determine exactly what could be making your fish sick without more information though. While ammonia is the most likely culprit, you may also want to test for pH, nitrite, and nitrate as well just to make sure those are at healthy levels.

      • Karyn says:

        Christina,
        Thank you for your response.
        Tyrone seems back to normal this morning (knock-on-wood :))
        He is swimming, eating, and it appears as though the “blood” spots are diminishing.

        This has happened a couple of times in the past. But this time seemed to last longer – almost a week!
        I only have the one fish & there is nothing else in the tank but the gravel and filter.
        I will certainly keep an eye on the water levels.
        Thank you again for the information!

    • Alannah says:

      hi karyn.
      our fish has that as well ( lying on the bottem of the tank. if you find any cures could you please reply.
      thanks

      • Karyn says:

        hi Alannah,
        I hope your fish is better by now. Tyrone just kind of got better on his own. I cleaned the tank, changed the water & filter, and he pepped back up.

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