Common goldfish diseases

Common goldfish diseases

Cared for goldfish rarely get sick, even when old. In the early days of an aquarium, however, when you’re still buying new fish for the tank, it’s very easy to introduce goldfish diseases or parasites.

Let’s consider the most common goldfish diseases:

  • White spot (aka ick, aka ich): Easily recognised by small white spots that appear over the goldfish’s body and fins. Highly contagious. If caught early when there are few spots, ick can be cured with off-the-shelf treatments you can buy from your usual retailer. You’ll need to treat the whole tank. The later stage, when the white spots are very numerous and the fish is breathing rapidly, is typically deadly, as the tiny parasites overwhelm the poor victim. Don’t delay!
  • Fungus: Fluffy cotton wool-like growths that appear on the fish’s body or tail, fish fungus responds well to proprietary treatments. Brief saltwater dips using special brine salts can also be effective, provided they don’t overly stress the fish. Since fungus typically only affects one fish at a time, it is best to move the patient to a separate hospital tank or large bowl, which should be kept clean via frequent changes of aged water. Note: A special kind of mouth fungus is much more difficult to treat, and may only respond to antibiotics from a vet.
  • Fin-rot: Ragged fins or a white-edged tail are the main symptoms of fin- or tail-rot. This disease is caused by bacteria, and usually only occurs in goldfish when a tank is over-crowded, under-filtered, or poorly maintained. Spring-cleaning the tank by performing several large water changes and boosting the filtration or aeration often leads to a recovery, but you must deal with the underlying cause. Proprietary anti-bacterial treatments are available; these are most effective in a separate hospital tank.
  • Dropsy: A bloated body and scales standing away from the fish are a sure sign of dropsy. This is one of the worst diseases your fish can possibly suffer from; no treatments are reliable. Afflicted fish must be removed from the aquarium immediately, before they infect their healthy brethren. You can try to cure the fish using (expensive) antibiotics if available from your vet. Keep the fish in a small standalone aquarium, kept clean by frequent (at least twice daily) water changes. You might alternatively try some tonic/brine, as per the manufacturer’s instructions. Sadly, in most cases the kindest thing to do is to put the unfortunate fish to sleep as humanely as possible rather than prolonging its suffering.
  • Skin flukes: These tiny creatures irritate the scales of the fish, causing it to flick and scratch against the rocks. Appropriate remedies from an aquarium store provide an effective cure; you may need to treat the whole tank, but it’s better to move affected fish to a hospital aquarium. Beware: white spot can cause similar symptoms yet the treatments required are different, so carefully observe your fish to ensure you make the correct diagnosis. It is usually a bad idea to mix two or more fish medicines.
  • Leeches: These are just what they sound like: wriggly leeches that attach to the body of the fish. They’re rare in aquariums, although they’re sometimes introduced with live food, but they can attach to goldfish kept in ponds. Catch the afflicted fish and give it a 20-minute dip in a light aquarium brine (or ‘tonic’) solution, made up according to the manufacturer’s instructions. The leech will typically drop off. If not, it will be more easily removed with tweezers. Look out for re-infestation
  • Gill flukes: If the fish hangs motionless in the water, particularly at the surface, with enraged red gills, suspect a case of gill flukes. This deadly disease can be treated if you spot it in time; consult your aquarium store as to the appropriate anti-fluke water treatment. The parasites are very contagious so you may need to treat the whole aquarium. Read the instructions carefully.

While many goldfish diseases can be beaten if caught early, prevention is far better than cure. A deterioration in water quality caused by a broken filter or careless over-feeding can easily stress your fishes, reducing their ability to fight off pests and infection, so keep your tank in tip-top condition.

In an ideal world you’d quarantine new purchases to save your fish and yourself a lot of headaches, but we realise in the real world not everyone does this. Please do consider setting up a small aquarium for quarantining new purchases. Once your tank is fully-stocked the quarantine unit can go into storage until called upon for hospital duties.

Remember, you are responsible for your own goldfish and their future health. By looking out for the common symptoms of goldfish diseases and responding swiftly by heading to your local store to buy the appropriate medicine (or better yet, having a few fish medicines already in your home in a goldfish disease first aid box), you can keep your fish in exceedingly fine fettle.

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Filed in: Diseases

57 Responses to “Common goldfish diseases”

  1. Poor fishie!

  2. Damn! my fish are dying of dropsy i guess!

  3. Question: My fish are covered in a hazy film that dulls
    their color. This I noticed yesterday. The day before that
    they were healthy and bright. I have lost 2 this morning.
    I live 6 hours from a pet store in Alaska. Any one know what
    this might be and maybe a home remedy I can use until the roads
    clear and I can get to an Anchorage pet store?

  4. I bought two fancy gold fish last nigh from the same tank and when I got them home in there new clean treated conditioned home one that is biger his fins look a little ragged and some silver spots like the orange scales came off, the other one is smaller and I get the all orange ones and this one has abot 4-5 black spots on it;s back fins, it is not markings or cilor off the fish it almost looks like very black fish poop stuck on them but I don’t think so. They both act fine and healthy otherwise,we even treated the water with this stuff that kills bad stuff in the tank but leaves healthy live something??? My fancy gold fish down stairs that we got from the same place weeks ago is just healthy and so beautiful. Do you know what this is and what shold I do???
    Thanks, Jen

  5. My daughter has had her beloved goldfish for nearly 3 years. It has been very playful and hungry up until now. We left it with its regular food to go on vacation, but with new “jewels” in its tank - much bigger and sharper than the regular pebbles beneath. Now its upper back is brown, it will not eat or swim much. I do not know if it was bruised trying to eat the food at the bottom of the tank. We also left it in a new tank, but I have now returned her old one and taken the jewels out. We’re really worried; I don’t think she’s eaten in a very long time. Can we do anything to save her?

  6. you mention (expensive) antibiotics for dropsey. Please, tell me what. Will tetracycline work?

  7. Jen some goldfish change colors with time. I’m no fish expert but one of my goldfish was orange when i bought it and a couple days later developed black spots that kept spreading. I was paranoid so I talked to my friend that works at petsmart and he said that some goldfish do change colors. I wouldnt be too worried about it as long as it looks and acts healthy.

  8. i got my goldfish a little over year ago now and he always seems to be unwell one week then fine the next but now he has stopped eating and has lost weight(well he looks really thin)i don’t Know what to do. Normally when hes ill i just put some of this blue stuff i got from the pet shop i got him from in the tank and he seems to get better but now he looks like he is getting worse. I got him from pets at home along with another fish who died the next day. I’m not sure my vet treats fish so any advice?

  9. i have a big gold fish named dorathy and i introduced two smaller fish into my tank and now the big one seems depressed mopping at the bottom of the tank. fist she was being very mean to one of the smaller fish pushing it around and stuff now she just seems to sleep alot. does she need an antidepressant of is she sick? or is it natural and dorathy will get over it?

  10. My year old goldfish looks really healthy–perfect scales and fins all erect ect. But for a week or more he has been staying near the bottom of the tank and not eating.
    He does look a bit bloated at his rear end–could he be constipated?
    Please could you advise me how to treat him before he gets worse.
    Best regards

  11. I have two comets. one 2yr old and one that i’ve had about 5 mnths. The smaller one seems to have fin rot (?). Have had no problems up to now and the big guy is fine. They are in a 10 gallon tank with a filter sized for a 5-15 gal. tank. I change the filter every two weeks and the water completely each month. I add water cleaner stuff at each water change and when adding water. Any idea what to do to help her?

  12. One of my Gold fish has lost his tail and I don’t think its because the other gold are biting him. Is there a condition that he may have?

  13. i have 2 gold fish and one has a gaping hole in the middle of its body, it has a few red spots also near to the sore, its eating normally but its behaviour is very odd, it will hide behind things plants etc, and spends a lot of time just sitting at the bottom of the tank,but my other fish is always trying to eat away at the other fishes sore, can anyone help and tell me what this could be? or what is best to do? Thanks :)

  14. Chris S…..This maybe fin rot i am not sure on medication but i am sure there will be one available in your local pet store.

  15. my poor goldfish is floating close to the top of the bowl and is very lathargic, it doesn’t have any other signs of disease I can see…what can I do to help him get better? or is this the end for the poort little guy?

  16. my mum brought my daughter two fancy goldfish for her birthday last yr. A couple of months later we changed the fish tank and the fish were doing really well, a couple of wks later we brought a black moor, fancy goldfish, from then we have had nothing but problems. First the black goldfish died, the other two followed, i did not see any spots or anything on them, they just became lifeless, went to the bottom of the tank and then soon died. We have cleaned the tank out, set it up for a wk, now the same thing seems to be happening again. Can anyone give me any tips on how to save the fish that i have left.

  17. help! my goldfish has stopped swimming around and just sits on the bottom and he has put down his fins on his back, what’s wrong with him??? please help?

  18. My poor baby is turning black around the face and gills. Few black spots on the fins also. What can cause this?

    Also, I have three gold fishes along. Two of them have lost one eye it normal?

  19. I have a question. My fish has a red stripe going from the top of his head imbetween his eyes to his chin, and i’v never reconized it befor. i had him for a year but i don’t he’s getting old. i think it may be a disease. do you think what it may be?

  20. I have two orange goldfish, and both are about a month old. I need to get a new tank because so far, they’ve caught all these diseases but have been cured.

  21. hi i have one fantail which seems to be suffering from dropsy i have bought the treatment to help but now another fantail is at the top of water and blowing bubbles. one fish died two days ago with no obvious signs of ill health my daughter is really upset i have done full water tests for amonia ph etc and all is fine please help…thanx

  22. My goldfish has stopped eating (not eaten for 6 weeks) and has litte lumps one on his head and 4 on his body, but the are not a funny colour. He sits at the bottom of the tank moping, he somethome darts to the surface and gasps the drops down again. I have tried anti bacterial treatments,salts and checked water quality which fine, not sure what else to do, he’s 7 years old now and I don’t want him to die?????

  23. Ooooohh, Chris, that sounds like he is in pain. If you are feeding it flakes, it would probably seize part of his pain if you change to pellets. You should also clean its tank more often and algea-eaters might be helpful to.

    ~Amanda Herget

  24. Chris,
    These are three simple things you could do to try to heal your fishes pain:
    1. feed your fish pellets, not flakes

    2.Clean its tank more often

    3.Buy algea eaters to put in the tank(the smaller, the better!)

    ~Amanda Herget

  25. When I say Chris, I mean Chris S

  26. One of my three fish has been lurking at the bottom of the tank breathing rapidly all day and isn’t eating. my fish are about a week old and the other too fish are fine but this one fish looks sick he might be consipated but im not sure because he also has all the symptoms for chilodonella but im not sure if he has that because it sound like it would make the other fish sick too and i really dont want him to die. he jsut started moving again but is still breathing rapidly. whats wrong with him?

  27. my son’s fish is tipping and we cant find out whats wrong whith them and my son is worried.

  28. my son andrew his two fish will stay at the bottom of his fish tank and two years ago they wouldent eat they dident eat for two weeks.

  29. I have 6 gold fish, 5 off them look like they have blood on their fins and they are not acting right. What could this be and what can I do?

  30. I Have 2 Goldfishes, one of them seemed sick a couple of days ago. my wife woke me up at 4:30 am to tell me it has died. i’m reading your post because im afraid that the other one got contagion from it. i dont know what to do to the poor fellow. luckily my little daughter forgot a little bit about them recently., Sad.

  31. My fish is lazy! It lays on the bottom on the fish tank and does nothing but sit there, it eats like normally is fat and big… but something seems not right, it looks like it is hard for him to swim! O.o What is wrong? And can I make it better??

  32. I have had my goldfish for nearly two years. I have just one in a fairly large tank with various items. Since i have had it it always seems to float on the top of the water the right way up not upside down or anything. It eats fine and loves its food but i want to know why it keeps floating as i want it to be happy.
    Please if anyone has any answers as what to do please help.

  33. my fish is laying at the bottom of his tank his fins are all tusked in his body he wont eat and he dosent move either i dont really know if this may help but when i got him a while ago he used to have these markings on his face but they faded away over time what do you think is wrong with him ,mary

  34. hello my Fancy Goldfish seems to just lay in the corner of the bottom of the tank under one of the plants and she also has one totally black eye. the fish also does not seem to be growing. what could be the cause? I also have another fancy in the same tank and he seems happy and hes growing and everything. I got the two fish at the same time also.
    Thank you in advance for any replys! :)

  35. Ok so 3 days of my fish sitting at the bottom of his tank I took him to petstock they they tested the water and could only find the “hardness” of the water was low and gave me ‘gold salt’ he’s starting to perk up slowly though

  36. My fish seems to have had the bladder disease where it floated upside down. I put skinned peas and now it just stays at the bottom. Not much movement. It has these scratches and redness on its body and fins. It also has had white growths. It is about 10 years old. I DONT KNOW WHat to do for it.

  37. My fish had been upside down, not really moving. I gave him peas without skin and looks better, but now just stays . He stays at the bottom of tank. Breathing seems struggled. He also has had white growths for a while now. He is about 10 years old.
    I DONT KNOW what to do. Any suggestions. Fantail goldfish

  38. I’m happy my goldfish doesn’t have these diseases. :) But just in case, I bookmarked this page. By the way, you said that you could find goldfish medicine at pet stores. Do you think PetSmart will carry these medicines?

  39. to treat fungus how much salt do i add to 5 liters of water

  40. I have a pond in the front yard with 11 goldfish in it,I have had most of them for about 4or5 years(school carnival) I have one my

  41. I have a pond in the frontyard with 11 goldfish in it. I have had them for 4or5 years(school carnivals)there is one in there that my grandaughter named handsom as he has such pretty gold and white markings,but the last couple of months he started changing colors,more white didn’t think much of it,but now he has no color almost looks like an albino and seems to stay in the rocks and doesn’t swim with the rest of the fish as much.
    Is this a diseases or can this be normal?

  42. My comet goldfish goes to the top of the tank and blows bubbles after I feed her. Should I be concerned? I have a 20 gallon tank with excellent filtration and only 2 comets in the tank.

  43. my 2 gold fish just recently died of the same causes 1 before the other though, and they shared the same tanked the face, underbody, and fins turned black the face was completly black the first fish that had died of this was brown before but lost his “coat” and than he got this and i havent been able to find anything on it both my fish had this and one died at the time im posting this plz can someone help me so it doesnt happen anymore to me???

  44. I got five gold fish and I took them out of a five gallon aquarium and put them in a 25 gallon aquarium and there all in the corner fighting with the fefliction of them self but they two or three does has brown spot on there top of there fins so are they sick and do I need to cover the glass so they want see there reflection. thank you brenda

  45. I just brought home 2 feeder goldfish in November. One died this past afternoon. It was perfectly healthy. As I took it out of the tank I noticed it’s sides were a bout bruised. Was it a sickness? Also, my second feeder goldfish is developing black spots on it’s tail fin. Thanks in advance

  46. well our fish has white stuff on his head we think it might be fungus but he is also been looking like he is dead. he has been laying low and then today he looks dead.

  47. I have 2 large goldfish. I’ve had them a little over a year. Recently one of my Goldfish got sick with Ick. I treated both of them and did everything I was suppose to including changing the water. About the 3rd day treating them for Ick. The goldfish that had Ick started flipping out banging himself into the glass and rocks after a few seconds of him going crazy he would start floating upside down and gasping for air. Then like 15 to 20 mins later he started acting normal. He’s been doing this once or twice a day for the past week. He doesn’t really have an appetite like he used to if not any and he’s starting to get red marks on his skin kind of like bruising. The other fish seems to be perfectly fine and hasn’t changed any behavior. Please help me!! What can I do?

  48. My fish had itche I treated with medication, few weeks later he got bouncy issues sits on the bottom then lies on its side,sits back up again can’t swim good then lies on its back. Should I put him down? Or is there anyway to treat it’s?

  49. Hi. I have a goldfish that is poorly. I suspect he had cotton wool like growth on his face. It started as a white lump then by the next day it was coming out in to I’m guessing the Cotton wool growth I went to the pet shop and bought pimafix for fungal infections. The same day I got home and the growth had fallen off his face altogether. I still started the treatment for 7 days and did another 25% water change. However since adding the treatment my fish hasn’t got any growths but has started to sit on the bottom of the tank and not eating for 2 weeks now. I have done 2 water changes since and still no better. Could it be swim bladder? Should I get treatment for him? His front two fins also look a little odd they look more crumpled? But I’m not sure now if he had always had that. Also today he was shaking a little like having a short of spasm where his mouth was trembling a bit. Please help I don’t want him to die!

  50. Hey Jennifer,

    I hope you had found a solution for your fish. At a petshop you can find pills that are specifically for Ick. My fished got ick one time I bought other fishes, and I have gone to the pet shop several times and bought one that was a powder and another one was a pill (size of a quarter) both of them were kind of blueish.

  51. One of my two goldfish seems to have blood in his eye. We got him 2-3 months ago. He is a black moor goldfish, and the oter is a fancy goldfish. He has been fine until now, the other one has been sick though. Yesterday we cleaned their tank and it was the first time since we had gotten him. We put him in his container while we were cleaning it and he kept bumping the side of the glass. I think he was freaked out and attacked himself. I don’t know what do. He is only a baby, so I don’t want him to die!

  52. My gold fish has scales that are hanging down, it almost looks like fuzz, you can tell it’s his scales but it looks terrible! I got him about 2 to 3 months ago, when I started reading through this I did not see
    Any thing about it, any ideas on what I could do about it😐🐠

  53. My fish has a orange spot on his back and a black spot inside of the
    orange one. From what I have just read I think it is leeches.
    Is there anyway to treat the whole pond (300 to 400 gallons) as catching the fish is almost impossible. Also will the leeches spread to other fishes? I have 20 or so fishes.
    thank you, linda

  54. I have 2 goldfishes they were very active and suddenly one of them goes to the top of the tank and blows bubbles looks like a froth getting deposited at the corners of the aquarium,. It’s tail is becoming transparent and fine hair like structures hanging at the end and after a while falling of upon movement. It was a voracious eater, but now suddenly stopped eating. The eyes were very clear but now they are covered with a pale white like cover, I am not sure what might be the reason.
    Should I be concerned? What do I do to overcome this problem. I have a 20 gallon tank with excellent filtration and only 2 fishesin the tank.

  55. Hi, I have 2 fantail goldfish and they are really old but they got red streaks in their tails and started laying on their sides and sometimes upside down. I purchased a canister filter pump for better filtration, I have airstones in the tank and an airation pump also. I thought they had swim bladder disease so I fed them skinned peas. I am doing 2 water changes a week and using prime with each water change. At present I cannot get the ammonia down even with ammo lok. It is a 55 gal tank. Now the ph is low. How do I bring it up without using more chemicals? I don’t want to lose my fish, please help. Thank you.

  56. I am the same person with the fantails. I forgot to mention that my fish still continue to have a ravenous appetite. What could be wrong with them?

    I have a number of goldfish that are quite big and now in an outside pond and have been for some years now. One of the fish is fat and looks pregnant, but the downside is that it lays on the bottom, it does occasionally swim.. but not a lot at all, and if the sun is shining it comes to the top and lays on its side. Do I need to send my fish to heaven, I do hope not as I love everyone of my fish. it will really upset me to have to do that.

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