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 posted (click the link at the very bottom of the page to view previous comments). Your question might be answered already! And always test the water before writing a comment.
This is the first part in the goldfish disease series. In this three-part series, you’ll learn…
- How to tell if your goldfish is sick (we’ll look at 14 goldfish disease symptoms)
- How to treat 7 of the most common goldfish diseases in aquariums and freshwater ponds
- 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 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. This will make it easier later 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 – One or more of your goldfish might be 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. If you notice gasping at the surface, test the water with a freshwater test kit immediately.
- 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 (and sometimes feeding peas will help). 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. 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 pop eye or 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 to 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. We’ll discuss more about this in the third part of the series.
You’ll then be able to take measures to ensure your other goldfish don’t get similarly infected.
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!
194 comments
one of my goldfish has developed a black mark on its nose similar to a bruise. is this something i should worry about or just where it has bumped it in the tank?
Hi Joanne,
Sounds like your goldfish might have an ammonia burn. These happen under poor water conditions and can be common in new tanks with high ammonia spikes, especially when the aquarium hasn’t been through the nitrogen cycle yet. How large is the aquarium you’re using? Have you tested the water with an aquarium testing kit?
If your fish are showing signs of ammonia burns, I’d suggest doing a 25% water change, then finding the root cause of the problem. If you’re overcrowding (the tank is too small to accommodate the number of goldfish you have), you’ll want to do regular water changes every couple of days (or even daily) until you can upgrade the aquarium (remember: you’ll need at least 20 gallons for the first goldfish plus 10 gallons for each additional fancy goldfish | for comets, commons, or shubunkins, you’ll need 20 additional gallons for every goldfish).
If overfeeding is the problem, you can gradually reduce feeding or the amount being fed during munch time. Only feed your fish as much as they can consume within a few minutes and reduce feeding to once per day if you have to.
Ammonia spikes can be lethal, so if your fish do indeed have ammonia burns, keep doing those water changes until ammonia levels lower to an ideal range (0ppm or below 0.25ppm if cycling). There are also conditioners that can help raise or lower pH and ammonia.
Hi Christina,
We love your website– it’s both highly informative and beautifully designed. Kudos and thank you!
So… We are having a MAJOR CRISIS in our tank. OVERNIGHT our GORGEOUS Telescope Moor developed what might be a bacterial/fungal infection or Ich and extremely frayed fins. Entire patches of his/her velvet skin and scales are missing. There are signs of irritation as well as protruding scales and what look like white sores. His/her tail fin was one of the most graceful aspects of the entire aesthetic of the tank. It’s heart-breaking to see such a beautiful, active fish get sick SO quickly!
Now, the companion goldfish who was purchased at the same time but has a calico-like pattern and doesn’t have the protruding eyes (or the grace) of the Moor is showing similar signs of disease. Because we have a 55 gallon tank of non-aggressive community fish (with a few fry) our immediate impression was not that their ‘wounds’ were inflicted by the other fish. However, upon closer examination everyone in the family has seen smaller fish take little bites or jabs at the Moor and the other Goldfish (simply because they are weaker and can’t defend themselves?) Size-wise, the two Goldfish are the biggest fish in the tank. We have no Cichlids or other aggressive fish. My husband pointed out that the day before the Moor got visibly sick, we had cleaned the filters. As of right now the Moor and the other Goldie are getting worse by the minute…WHAT DO WE DO? We don’t have a hospital tank. We have an isolation ‘booth’ that hangs over the side of the tank and was made for isolating fry– the Moor would be even more stressed and would have NO wiggle room in the isolation ‘booth.’ Please help us! Thank You!
– the Fire-Asch Family
Hi Sarah,
It sounds like your goldfish might have gotten into a scuffle and the wounds developed into a more serious infection. Some otherwise peaceful fish just can’t help themselves when they see goldfish with elaborate fins, which is probably why your poor telescope moor got picked on the most. Fin nipping doesn’t exactly happen because your goldfish are weaker. Many fish, regardless of size, find flowing fins to be very tempting chew toys. Or you might just have a fish that is very territorial.
Are any of your other fish showing signs of sickness? I know you mentioned that patches of skin and scales are missing, but can you describe the bacterial/fungal/ich infection you’re noticing?
Based on the missing scales and shredded fins, it really sounds like at least one of your fish got too carried away with the fin nipping. My first suggestion would be either to isolate your goldfish or isolate the culprit(s) doing the fin nipping. Preferably put your goldfish in a hospital tank for treatment. Even a bucket or small tub could work as a short-term solution if you don’t have a hospital aquarium to use (just make doubly sure there’s no soap residue!). If a small hospital aquarium doesn’t fit your budget, you could shop around for an inexpensive 5-gallon bucket. Ideally you would want 10 gallons at the very minimum, but 5 gallons might work in this case as long as you rigorously change the water daily (25-35%) until you can buy a permanent home for your goldfish. You can also try getting a tank divider to separate your goldfish from your tropicals.
If isolating your goldfish is not an option, you can try isolating the fin nipping culprits. Since they’re smaller fish, you can probably get away with much smaller tank arrangements. Do your research though to make sure the size aquarium fits their specific needs.
Now you’ll want to begin treating your goldfish. First of all, how are water readings? If unsure, do a quick test with a freshwater kit. If ammonia, pH, nitrite, and nitrate levels are where they should be, you can start the healing process. If not, fix whatever is causing the poor water quality, because most likely this will cause your goldfish even more stress and make it tougher for them to heal.
Without knowing exactly what your goldfish are suffering from (besides the obvious wounds), it’s hard to say what treatment to use. But you can start off by slipping in some aquarium salt to reduce stress (1/2 rounded teaspoon for every gallon of water – that’s 27 1/2 rounded teaspoons for 55 gallons). To speed up the healing process, you can give your goldfish Melafix. Some hobbyists absolutely hate the product, claiming it to be useless and very hard to get rid of after treatment. But still there are a large group of people who have successfully healed their fish with it, so it might be worth a shot. Of course, you can also wait it out and let your goldfish heal naturally.
Definitely let me know about the fungal/bacterial/ich infection. You’ll want to deal with this right away before it spreads/gets worse and potentially infects your other fish.
One of my goldfish is laying on its side.
Breydon, what do water tests indicate when you test the aquarium water? How large is your aquarium and how many goldfish do you keep? There could be a number of reasons why your goldfish is lying on its side, but it’s hard to know why without any more information.
i just got my two goldfish at the fair yeaterday and all i have to feed them is betta food for now! but they refuse to eatit. is there something im doing wrong besides the fact that its not goldfish food? how long will they be able to live without eating? 🙁
by the way i am going to be getting goldfish food as soon as possible
Zoe, goldfish are usually ravenous eaters, so if they’re not eating for you, that’s a sure sign that something’s wrong. Have you tested the water with a freshwater testing kit? If so, how are ammonia, pH, nitrite, and nitrate levels?
Fair goldfish are generally in poor condition after sitting in a plastic bag in the hot sun all day. Your goldfish could have gotten sick during the time between getting him and bringing him home with you.
Also, since bettas are carnivores and goldfish are omnivores, you should try supplementing your goldfish’s diet with greens – like chopped spinach or lettuce. You can also boil broccoli or peas until you can buy goldfish food.
Hello, I have a 4 year old common goldfish. She presented a lump UNDER the skin just behind her left gill on June 11th 2012. I’ve treated her with oxolinic acid antibiotic for 10 days. During the 5the day of treatment she started to become bloated and began to show a similliar lump on the right side along with protruding eyes. About three days ago her bloating was gone and her eye receaded but her original lump is still there and getting larger (slowly). I was given panacur c canine dewormer but havent treated her yet. I plan to today. She has been very lathargic from the meds. Only in the past 3 days has she “come out of it”. Any ideas what it might be? (The subcutaneous lump)
Thank you
Vince C
Hi Vince,
Sounds like your goldfish might have had an internal parasite or tumor. While I’m not familiar with panacur c canine dewormer, I wouldn’t use it on fish since it seems like it’s specifically for dogs and not goldfish. For internal parasites, there are safe treatments available in pet stores. If the lump is a tumor, there’s really little you can do. Sometimes tumors can reduce in size on their own, but most times it will stay visible on your goldfish and might grow. Just continue to keep your goldfish comfortable in good water conditions and watch for other signs of infection. You can try the salt treatment mentioned in my ich treatment guide or a medication like Prazi Pro.
It is imperative to catch these kinds of symptoms so you can avoid any more harm to your fish. However, you don’t have to be too hard on yourself if you lost a gold fish or 2. Like any other thing, you’ll develop a habit of looking and checking your fish, then it’ll be easy to spot these symptoms.
Thanks for the tip, James. Many people do lose a goldfish at least once in their lifetime – it’s sad but it’s true. Hopefully you’ll learn from your mistakes and do the research next time around so that you don’t lose another!
My goldfish jumped out of his tank today when we were setting it up and I didn’t notice, he was their for at least 45 secs then I put him back in the tank now he’s swimming at the bottom he also isn’t eating as much as he used to, is he truamatized, sick or a broken fin
Oh no! I’m so sorry to hear that Alex. It does sound like something could be seriously wrong. Did you use tap water? If so, did you condition the water with something like AquaSafe? Tap water is often filled with harmful toxins, and goldfish placed in such water without having it conditioned first (or at least letting the water sit for 24 hours) will result in dead fish… sometimes within the next couple of hours.
If tap water isn’t the problem, have you tested the water recently? Ammonia spikes happen often, since goldfish excrete so much waste. I recommend testing the water on a weekly basis to prevent such spikes from occurring. How large is your aquarium?
I certainly hope your goldfish is okay!
ive been overseas for 8 weeks now my pond has a lot of slime in it now i see by black gold fish has white patches about the size of my thiumb nail. hes swimming just fine but the white patches are not menat to be there/ i intended to drain the lilly pond and put clean water and get the water pump operating daily.
Hi Rex,
It sounds like your goldfish might have picked up a fungal infection. I recommend using Methylene Blue for treatment, since this medication seems to work very well on sensitive fish with fungal infections.
I would move your fish to a hospital tank before you begin treatment. This will also give you time to test the pond water and determine what caused the infection.
my gold fish has a fluffy patch growing above its mouth I have it in a hospital tank what can i do for the little fellow
Hi Ross,
Your goldfish probably had a fungus infection or what is known as cotton mouth. First, I would test the water immediately, as you should probably find out what caused cotton mouth in the first place (the main culprit is almost always poor water quality).
Some goldfish hobbyists use Pimafix to treat fungal infections, while others like to stay away from the Melafix/Pimafix combo. I personally recommend Methylene Blue, as it seems to work quite well for sensitive fish with fungal infections.
Before treatment, always take out the activated carbon in your filter though, or it might reduce effects of the medication.
I have two 3 inch long goldfish and they are in a 130 gal pond with other fish. these two are staying close to the surface and moving slowly. they have raised scales in some areas but no wounds and not eating. I put them in a salt bath for 10 minutes. I took out 40 gals of water from the pond and refilled the pond. But I’m not sure what they have so I can treat them. shelia
Raised scales sounds to me like dropsy. Your goldfish could have also just been constipated.
I would move your goldfish to a hospital tank before you begin treatment. It’s difficult to treat buoyancy problems, especially since they might have been caused by a number of factors – poor water quality, kidney failure, internal infections. I would start off by feeding your goldfish frozen peas (de-skinned) and see if that solves the problem.
If your goldfish still look bloated after a few days, limit feeding for a while (this will help any constipation). You can also try Maracyn Two, as this might treat some forms of dropsy (but keep in mind that it doesn’t treat all dropsy). Continue to keep your fish comfortable in clean water and make sure the aquarium is well-oxygenated.
You should also test the pond water to make sure water readings are in the safe range.
My goldies are in a pond& are several years old. One split tail goldie has become unbelievably fat. All else about him(?) is good. what do you think is happening to him?? What should I do ?? Loretta
Loretta – are the scales sticking out like pine cones? This could be an indication of dropsy, which is a very difficult disease to treat. You can try moving the fish to a hospital tank and then treating him with aquarium salt. Many hobbyists recommend to use 1 tsp per gallon.
If your fish doesn’t respond to the salt treatment after a few weeks, you could try medicating. Some hobbyists recommend Maracyn-Two to cure some forms of dropsy. But even medicating might not work, since dropsy is caused by a number of different factors, such as kidney failure, internal infections, and poor water quality. Without knowing the cause, it will be harder to treat. In many cases, the goldfish is lost. :/
If your goldfish just appears to be bloated and having buoyancy problems, you can try feeding him frozen peas. Just cut off the skin and slice it a bit before feeding.
As always, you should try to figure out what caused the problem in the first place. Do some water tests with a freshwater aquarium testing kit. I personally use the API Freshwater Test Kit. It’s very accurate and I haven’t ever had a problem. Test for pH, Ammonia, Nitrite, and Nitrate. Read the instructions on the kit and make sure results are in the safe range. If they aren’t, the kit should give you suggestions on what to do next. You can also ask for advice from the goldfish community here.
I hope your goldfish gets better!
My goldfish are over a year old, about 7″ long & 3 1/2″ wide (very healthy}. I noticed another type of fish was pecking at them and they had lost nearly 90% of their scales. I removed the problem fish but what can be done about the scaleless goldfish?
this sounds strange, but im desperate for an answer, please email me!
Our goldfish is fancytail type, last night i fed him a half a pea and a bit of undyed maggot , i happily turned away then ten minutes later i looked over to check hed eaten it all and his whole face had changed SHAPE! His mouth now is in the shape of a bottom feeder with protuding top lip and under his mouth where his gills are its all sucked in and not rounded as it was before, its bizzare, hes like a new fish! Hes always been healthly and well looked after,has he swallowed something and got it stuck?ive popped him in his quaranteen tank and cleaned the main tank including gravel with 25percent water change…help! Hes been like this for 24 hours but is happily feeding and greeting me at the tank, we love him very much!
My goldfish have a bright red spot between their eyes above their mouth, could this be just their color?
It’s possible, Linda. If it spreads, it could also be a bacteria or parasite infection. Do some water tests and monitor results. Make sure pH, ammonia, nitrite, and nitrate all stay in the safe range. Poor water quality can result in stress and infection. Stress is also one of the leading causes of most goldfish problems.
Loved this site and bookmarked it for future use. My son had won a goldfish at the local fair ( of course it died). We got a replacement from the local fish store, and a small tank with all the extras. My son and the whole family have gotten quite attached to him, and this site has definitely opened my eyes to how best to care for him. Thanks and keep up the good work.
PS: going back to our fish store tomorrow to buy a bigger tank!
Congratulations on the new goldfish! I’m so happy to hear this site has helped jump start your fish keeping hobby. Keeping goldfish can certainly be exciting. With care and loving attention, I’m sure your fish will thrive for many years to come!
my fish has something growing on his fin…looks like part of the fin but its white (my fish is black)also its grown a lot in 2 days and his underbelly is turning silverish??? is he sick