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
Mar 10th, 2008 at 11:15 am
Poor fishie!
Sep 15th, 2008 at 12:49 pm
Damn! my fish are dying of dropsy i guess!
Jan 18th, 2009 at 3:24 pm
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?
Feb 26th, 2009 at 10:29 am
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
Apr 29th, 2009 at 8:10 pm
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?
May 7th, 2009 at 12:19 am
you mention (expensive) antibiotics for dropsey. Please, tell me what. Will tetracycline work?
Jul 11th, 2009 at 10:45 pm
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.
Aug 17th, 2009 at 3:41 pm
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?
Sep 20th, 2009 at 9:46 pm
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?
Nov 5th, 2009 at 4:22 am
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
Feb 27th, 2010 at 8:54 am
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?
Mar 10th, 2010 at 10:29 am
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?
Apr 8th, 2010 at 8:48 am
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
Apr 8th, 2010 at 8:50 am
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.
Apr 11th, 2010 at 6:37 pm
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?
Apr 12th, 2010 at 6:07 am
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.
Apr 20th, 2010 at 5:09 pm
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?
May 4th, 2010 at 12:19 pm
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 each.is it normal?
May 8th, 2010 at 11:04 am
tengo 6 bailarinas en una pecera grande y comoda, me regalaron otra grandota y bella, ella esta sola en una pecera pequeña y casi no subia todo el tiempo abajo, yo la lleve a mi pecera y se comporto muy bien con mis otros peces, ya han pasado 4 dias y mis peces al igual a la que me regalaron estas abajo se esconden y se ven triste, no suben solo cuando lo pongo su comida y vuelven a bajar, ya saque la q me regalaron cambie el agua, igual siguen abajo… me preucupan mis peces… auxiiiiiiiilio
May 14th, 2010 at 4:56 pm
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?
Jun 18th, 2010 at 11:21 am
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.
Jun 25th, 2010 at 3:00 am
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