Treating Fin and Tail Rot On Goldfish

By Jamie Boyle

Before you learn how to treat fin and tail rot on goldfish you first need to make sure you have properly diagnosed your goldfish illness. So what is fin and tail rot you may ask? Fin and tail rot is a goldfish disease that you can see that affects the fins and tail that appears to be rotting away. If left untreated the fin and tail will rot right to the body itself. You will know its fin and tail rot as you will see ragged, ripped,frayed and torn fins whith a white-pinkish layer at the edges and often red streaks as well. The good news about fin and tail rot on goldfish is that it’s easily treatable.

What Causes Fin and Tail Rot On Goldfish?

The cause of fin and tail rot beginning on goldfish is a bacterial infection has set in. Bacterial infections are mainly caused by poor water quality. As I’ve said it many times and I will say it again, the #1 reason fish get sich is because of water quality. They become stressed, there immune system lowers and goldfish parasites attack or bacterial infections arise. Another cause for fin and tail rot developing on goldfish is sometimes a result of an injury your goldfish have suffered. The most common cause of fin and tail rot is usually poor water quality.

How Do I Treat Fin And Tail Rot On Goldfish?

You can treat fin and tail rot on goldfish with several medications. The ones I like to use are Melachite Green and Melafix. Melachite Green works very well but it’s more harsh then Melafix but it works. With Melafix it’s an all natural medication that won’t disturb your biological filter. Melafix also work well at healing goldfish and rejuvenating tissue. The PondCare melafix I beleive is one cap full for every 50 gallons. Please read manufacturers label for recommended dosage. You can also buy Melafix for aquariums as well.

Just the other day I was reading an interesting article about treating fin and tail rot with peroxide. I myself have never tried that myself but I have used iodine to treat fin and tail rot. Sometimes there are household products that can work but medication specifically for fin and tail rot for goldfish is much better.

Is there anything I can do to prevent fin and tail rot from happening in the first place?

The best way to prevent fin and tail rot from happening on your goldfish would be to make sure you maintain your water quality. Do water tests on a regular basis to make sure fish don’t become stressed and living in poor water quality. A proper maintenance shedule that you stick to will help prevent many goldfish diseases from happening in the first place. Don’t want fin and tail rot to happen to your goldfish? Then proper goldfish care is essential to have healthy goldfish.


Jamie Boyle
The Goldfish Guy
“Helping Goldfish Owners With Advice, Fish Care and Fish Medication Treatments for Goldfish Diseases, Illnesses and Parasites”

32 comments on “Treating Fin and Tail Rot On Goldfish

  1. Hi Jamie.My fish recoverd from ich using rid-ich for 5 days. One fancy fish though got secondary infection, tail rot. I purchased triple something capsules but was very strong and made her weak. Did well in big tank for 2 days but then bottom sat. Now she is in a 3-4 gal fishbowl and I bought a jet stream 600 for 5 gal tanks. I hope that isn’t too much oxygen for her. I leave it on for a while then turn off for a while. I bought API liquid fungus cure for fin rot. Hopefully that will be better for her. She is swimming around crazy with oxygen. Too much? Or good. The Koi that is the same age as her picks on her sometimes in the tank. Koi used to pick on other fish that died 4 weeks ago. Hopefully once healed this fish will be okay to return to tank with others. I have the koi(1/5-2inchs L) and two very small new goldfish recently added that caused the ich in the first place. Meds calls for 1 tsp. per 5 gal so I gave just under. Using aqua stuff for new water changes and tsp. of salt. Do I use salt with these meds? She loves the big tank and I don’t want a fish bowl to be her new home.

  2. I used Melafix on my ‘Aunt Denise’ goldfish who got tail rot as a secondary infection after ich. Melafix has made her worse actually. I read an article that Melafix only kills certain bacterias and the manufacturer’s are not sure exact ones. So Melafix can either kill the infection or Melafix can act like food and cause the bacteria to multiply faster and continue to hurt the fish. My poor fish has rapidly in 1 day had her fins shred even more. She is a fighter though. I will do a 25%+ water change and use the Rid-ich or other liquid med I have that is to kill tailrot/finrot. You can do a search on Melafix and read for yourself the reviews and studies on that medication of the pros and cons. Thank goodness I read it or my poor fish would deteriorate even more.

  3. Jamie Boyle on said:

    Hi Rose,Sorry to hear about your goldfish.Your right Melafix does treat certain things only however Melafix does work effectively at treating fin and tail rot and helps promote new tissue growth. I have used many types of medications on fish and the most fish I’ve had at one time was estimated at around 20,000 at Country Koi Fish Farm.I’m not sure why Melafix didn’t work with treating your goldfish for fin and tail rot. It should not have made it worse. The thing is all medications don’t guarrantee that your goldfish will get better. You see it depends on how bad the situation is. Sometimes fish get so sick and then when you begin treating them they get more stressed, get worse and die. Treating fish can cause more stress on them.How bad was the fin and tail rot on your goldfish? Was the fins and tails completely eaten away and gone?I do stand by Melafix as I’ve used it many times and have had great results. The thing with the internet is that people have opinions, we all do. I always say never believe anything you read on the internet until you’ve researched it for yourself. At the end it’s up to you to decide what you think is right and make a judgement call. The truth is not everyone will get along, everyone will not agree on everything that is what makes us humans. I can only tell people what my results are with the product and how well it worked for me. What happens sometimes and quite frequently is that people mis-diagnose the disease and treat with the wrong medications. Then they go online make a post saying Melafix does not treat fin and tail rot when it happens that the person did not use the right medication. So Rose there are many things that could have happened but just like us when we get sick certain medications will work for us and other may not for others. So if you have a different medication then by all means try it and see if your goldfish gets better. I hope it does. I’m here to help but at the end people will either trust me or seek other advice. As my saying goes and I know I do it in my life is always seek a second opinion.So try the new medication for your goldfish and let me know if it works.Also I seen you asked me about using salt when treating fish with medications. Never treat with salt at the same time with other medications. Salt can cause treatments to be very toxic to fish. A good example is that you should never treat with salt while using Melachite green it can kill your fish. I would never mix medications or use salt when treating with one. You never know what the combination will do.Let me know how ‘Aunt Denise’ is doing. I wish him well.Sincerely,Jamie BoyleThe Goldfish Guy

  4. Hi,I hope you might be able to help us. Our son’s gold fish (Fishy Fish #1) joined our family in June by way of a carnival. Although the other fish he came with died right away, FF1 has grown leaps and bounds and up til now has been quite healthy. Last month he did have some reddish streaks and what looked like fin rot, but my husband started changing his water more regularly and that cleared up. In the past few days, I’ve noticed that FF1’s mouth looks like it is growing over!! The right side of his mouth seems to have a thin layer of skin growing over and in it. I’m worried it will grow over completely and he will die! Please let us know if you have heard of this before, know what it could be, and how to treat it.Thanks!!!!!

  5. Jamie Boyle on said:

    Hi Meg,Goldfish do become a part of the family eh 🙂 I’m glad to hear that he has been doing well up until now. You see water quality can cause many goldfish diseases and sickness among fish. This is the #1 reason that diseases occur or parasite outbreaks. Reddish streaks on fins and body is a symptom of poor water quality. I’m glad that your husband began doing more water changes and maintenance on your aquarium or goldfish bowl.Do you keep your goldfish in a tank or bowl?As for the skin growth over the mouth of your goldfish I believe it may be a tumor growing. There are two types of tumors it may be, benign or malignant. Malignant tumors are ones that spread quite rapidly and is not really treatable. The good news is that if it is a benign tumor, you can actually have it surgically removed. I would need to see a picture of this to be more certain but this is what it sounds like.By the way, what type of goldfish do you have? Is this a normal goldfish or is this an oranda or red cap oranda in which there crown can actually grow over their mouth making them unable to eat.Curious, get back to me and I will try and offer you some more goldfish assistance.Look forward to hearing from you soon.Sincerely,Jamie BoyleThe Goldfish Guy

  6. Thank you so much for your quick response!! I keep checking this fish every five minutes to make sure it is still alive!! I took some pictures and attached them here.Especially in the second picture, you can clearly see how small the opening of the fish mouth has become. It looks sort of like a crescent moon and is not a trick of the light, that is literally all the mouth that is left open.I can’t imagine being able to afford fish surgery, but my husband suggested trying to hold the fish and open the skin with tweezers! I think that might hurt the fish even more. Can you recommend anything to save our fish? If not, is there a way tht we can put him to sleep gently and without pain? I do not want him to suffocate! Thank you sooo much for your help with this.[IMG][/IMG]direct link to pics:[IMG][/IMG]

  7. Hi sorry to reply again but I forgot to respond to your other questions. As you can hopefully see from the pics, I believe our fish is not an oranda, but I think a regular comet. We keep him in a 5 gallon tank with filter. Thanks again!!

  8. Jamie Boyle on said:

    Hi Meg,Your very welcome! You actually reached me at a good time as I am working on a few of my other websites I am working on. So I see your email right away. :)Thanks for giving me the links to your goldfish pictures. Yes you do have a regular goldfish. The question I have for you, was it like this when you won it at the carnival. You see goldfish go through an intense breeding program and goldfish breeders cull through the baby goldfish only selecting the best quality fish available on the market. What they do is cull out any baby goldfish with deformities such as curved spine, mouth deformities, missing fins and protruding gills. I don’t believe this is a tumor. I do see that the opening of the mouth of your goldfish to be very small and deformed. The angle of the photo was not clear for the mouth but is there a white patch by the mouth almost like body fungus that goldfish develop. You may have some mouth fungus and I did notice that your goldfish has cloudy eye. When you look at the picture of your goldfish or look into your tank there is a white grey film over the eyes. This is called cloudy eye in which you can treat using Melafix. As far as the opening of the mouth I would just keep an eye on it and see how it progresses.How long have you noticed that the mouth of your goldfish was like this?As far as fish surgery, there are not a lot of people who do it. I know where I live veterinarians don’t even treat fish and I live in a fairly big city. I have treated fish for people for the public as well as business clients of mine as well. In order to perform any procedures on fish you will need to anesthesize your goldfish. There are several ways you can put a goldfish to sleep but I think we should just let it be for now and see if it gets worse.Your goldfish is eating right? How long have you noticed that the mouth of your goldfish was like this?Keep me informed and I will try and guide you through to keeping your goldfish healthy and alive.Sincerely,Jamie BoyleThe Goldfish Guy

  9. JamieI will get the Melafix first thing tomorrow morning and hope it is just mouth fungus. I started noticing this mouth closing about a week or two ago. I really noticed it again tonight and that it had gotten much worse. I think FF1 is pretty stressed because his breathing is very labored. He has been eating pretty normally as far as I can tell. He’s even been swimming pretty rapidly for the most part. Once tonight I saw him lying near his “ruin” (decoration) near the bottom of the tank but he rallied so he could have just been asleep. I cannot believe I am even writing about the sleeping habits of a goldfish. :)He was not deformed at all when we got him from the carnival. He was much smaller too, and in the span of just a few months has probably quadrupled his size. I guess if he lives we have alot to learn about keeping a healthy goldfish, I did not even notice the cloudy eye until you mentioned it. Thanks again, I know my son will appreciate it if his fish pulls through. I will keep you updated if FF1 gets better or worse.

  10. Jamie Boyle on said:

    Hi Meg,Yeah try using Melafix and see if that helps. It will treat your cloudy eye on your goldfish for sure and hope that it’s mouth fungus as well. We’ll see, time will tell and I hope your son’s goldfish gets better too. I hate to see a young boy lose his pet goldfish. :(If you need any help with treating your goldfish with Melafix please feel free to ask. The directions on the bottle are pretty well explained but if you need any help, I’m always here to help.The only thing with treating goldfish with any medications always make sure you have maximum aeration. Also remove your activated carbon as it will remove the medicine from the water making the treatment ineffective. Just a couple of goldfish tips I wanted to add when treating fish.One last question, when your goldfish feeds, a goldfish is able to dislocate their lower jaw making them able to pick up food at the bottom of an aquarium or pond, does your goldfish mouth open up bigger when it feeds if you noticed? Or is that opening as big as it gets even when it feeds?Need anymore help please feel free to ask.Sincerely,Jamie BoyleThe Goldfish

  11. Hi,Update on our fish: he seems to be getting worse after treating with Melafix. His fins seem to be shredding more and I’ve noticed a white “ball” spot on the top of his dorsal fin. Also he has had several bloody red spots. His mouth has not improved, but he is still eating. I don’t notice his lower jaw disengaging too much but he still loves to eat.The water in the tank has started to become much cloudier and danker looking even with changing at least 25% every few days.So, if you have any other suggestions for treating him, with these added symptoms, I’d appreciate them. Thanks again!

  12. Adam Yew Abdullah on said:

    Hi Jamie,My fish got white spot on its tails. Can u giv some ideal how to cuel it. Thanks.

  13. Anonymous on said:

    I am feeling really bad for my goldfish. I have a 30gallon which has housed two goldfish for some years with no problems, Spot and Lacey. I introduced a new fish (Tiny) to the tank. I kept her isolated for a few weeks to make sure she was healthy. I put her in the tank and a week later Spot had died and Lacey has serious fin rot. I’m treating with Melafix but she’s not getting better yet. Tiny still looks and is behaving normal, but I had to take him out of the main tank b/c he was biting Lacey’s fins. How can you tell if a new fish is going to put disease into your tank??Also- I am so sad for my sick fish, she looks awful. What else can I do to save her?

  14. Does Melafix help the goldfish grow it’s tail back?

  15. PetGoldfishForum on said:

    Hi Kevin,Yes Melafix does help grow fin tissue damage resulting from fin and tail rot. This will help treat your fish and get your goldfish health back to normal.To learn more about Melafix refer to my post and see how Melafix can treat fin and tail rot and restore damaged tissue on Goldfish.Need anymore help please feel free to ask.Sincerely,Jamie BoyleThe Goldfish GuyNeed More Help With Goldfish, Koi, and Ponds? Want To Talk To Others and Share Photos? Join Today!

  16. The Goldfish Guy on said:

    To the person whith Spot, Lacey and Tiny. I am sorry to hear that Spot has died. As far as what you are saying you did everything right. Some people suggest you quarantine any new fish for 4 weeks, but 2 weeks should be the bare minimum.Sometimes the fish may look okay but there are things you cannot see. He could have had gill parasites that damaged his gill tissue resulting in suffocation. Goldfish diseases and parasites are not quite easily seen.As far as Lacey with fina and tail rot Melafix will treat it. You did a good thing by taking out Tiny as with any fish when another fish is injured fish sense this and pick at them. This will help in Lacey’s recovery. From what you are saying Lacey sounds like she’s in bad shape. The fin and tail rot may have stressed her out too much beyond treatment. With anything in life there will come a point where we are too sick that medication will not help, same goes for your fish. Melafix does treat fin and tail rot but sounds like you have severe issue of it.Only thing you can do is wait. Just make sure water quality is perfect as if it’s not will cause more stress on your goldfish. Other then that you can try a different fish medication to treat it if that doesn’t seem to be working.Do you have the activated carbon taken out of your filter?Get back to me and I’ll see what I can do for you. In the meantime check out this medication that you may want to try Kordon Malachite Green Fish Medication For Ich, External Parasites and For Treating Fungal Infections this will do the trick.If you need anymore help please feel free to contact me anytime.Sincerely,Jamie BoyleThe Goldfish GuyNeed More Help With Goldfish, Koi, and Ponds? Want To Talk To Others and Share Photos? Join Today!

  17. Anonymous on said:

    Colloidal Silver is a God send….make sure it is a true colloidal. Silver Wings made in Nashville,Tn is a true colloidal. It’s an antibiotic that a human and pets, cats, dogs, and fish can use. I have put it in my cat’s ear when it was infected. Cleared it up within hours. I have given to my cat internally to kill parasites. It kills bacteria in fish tanks: I have put it in my eyes, ears, nose and throat, also put in on a cut. My son was sick, and he took it for about five days and he’s totally recovered.It really is great……hope this helps some people and their beloved pets. Bobbi

  18. on said:

    I don’t know about using Colloidal Silver. Lots of talk about it and I don’t know about everyone else but I wouldn’t want to turn into a Blue Man like Paul Karason from California known as Pappa Smurf. He turned blue using this.Me myself I’m not sure about this stuff but people can make their own decision on this. If it worked for you then great but people can make decide themselves. Only thing I will say before using anything research it on the pros and cons of any medication or treatment whether it’s for yourself, dogs, cats, or fish. Also seek professional advice from your doctor or veteranarian.Thanks for sharing!Sincerely,Jamie BoyleThe Goldfish GuyNeed Water Plants or Looking To Buy Garden Decor and Garden Fountains?

  19. Hi, I’ve recently become an adoptive mum to my flatmate’s goldfish, she doesnt really look after him that well so I have taken it upon myself to look after him. She has had him from July 08 and he has been healthy up until now. Today I have noticed a sort of cut, veiny thing on his fin tail and am worried it might be fin rot, but obviously I am not sure enough. I have cleaned out his tank today, scrubbing it down to make sure there is no bacteria and while doing so took some pics of him in the sink to see what you think might be wrong with him. I hope you can help. This has literally just appeared today and I am worried.Emma

  20. GoldfishCareInformation on said:

    Yeah I noticed where exactly the cut or fin and tail rot is. Normally it appears at the tip and ends of fins and tails on fish. This doesn’t.I don’t think this is fin and tail rot. I think you goldfish injured himself and has like a bacterial infection there. Regardless you should treat that goldfish using Melafix which treats bacterial infections and fin and tail rot.You can buy Melafix for fish treatment online and this will do the trick for you.Also always make sure you add water conditioner in when doing water changes to remove chlorine and heavy metals as well as add beneficial bacteria in your aquarium each time too.Use the Melafix to treat you goldfish and he’ll be fine in no time.Sincerely,Jamie BoyleThe Goldfish Guywww.GoldfishCareInformation.comNew Fish Forum – Goldfish, Koi and Ponds – Join Today!

  21. Hello Goldfish Guy,My fish are a few years old and for a few months one of them has had a cloudy white eye. I completely clean their tank every 3-4 weeks and they have a filter. I thought perhaps it was catarax of some kind as it seemed to come on gradually and didn’t blob out, but today the eye appears to be bleeding inside. He still seems to be ok within himself and appears to be moving the eye without discomfort but I’d really like to be able to help him.Many thanks,Jo.

  22. PetGoldfishForum on said:

    Hi Jo,It seems as though a bacterial infection has set it creating the red eye on your goldfish. You can treat bacterial infections using Melafix Antibacterial RemedyMelafix also treats against cloudy eye in goldfish. I think what your problem is that you have a water quality issue. You may be cleaning your aquarium too well causing nitrite and ammonia to spike due to not enough beneficial bacteria to break down fish waste.How do you clean your aquarium? Can you please elaborate on your comment, providing steps on what exactly you do:“I completely clean their tank every 3-4 weeks and they have a filter.”Hope to hear from you soon but I suspect a water quality issue that has caused cloudy eye and now bloody red eyes to appear on your goldfish.Talk to you soon,Jamie BoyleThe Goldfish GuyNew Pet Goldfish Forum – Join, Learn and Have Fun, Share Photos and more – Join Today!

  23. nithu on said:

    how to make my gold fish’s tail grow bigger in few advice me

  24. Christine on said:

    Hello,My Gold Fish looks like it has some Tail rot going on but has been at the bottom of the fish tank for a 2 days now and looks like its panting for Air. I got some Mardel – Maracyn meds for Body Fungus as well as added a Air Pump to my tank – Is there anything else I can do? I have had the Fish since Christmas and it has been very healthy since the past few days…today it couldnt make it to the top of my 10 Gallon to get food 🙁 if anyone could help i would really appreciate it!

  25. Arya's Mommy on said:

    Hi Jamie,We had 6 goldfish in our tank, inlcuding 2 beautiful orandas. All the fish were doing just fine. There were also 2 suckers (I think that's what they're called). About a month ago, we decided to add a few more fish to the tank. We bought a few tetras. And some silver dollars. Now, my knowledge of fish is limited. We've had the tank and the old fish for just above 7 – 8 months. Then, we introduced the new fish. While watching them the next morning, I noticed that all of their fins were bitten. It was horrible. I watched closely and noticed a few of the tetras biting the fins and holding onto it while it shredded. I immediately removed the offending tetras. When we bought the new fish, I specifically stated that I wanted fish compatible with my goldfish. I was relieved after that, but the next morning, I noticed that the silver dollars were also biting their fins. Separated them too. Then, the tank looked so depressing, so we got 2 new goldfish. They were really scared at first in their new home, but after a while one of them got quite aggressive… and I saw him going after the older goldfish quite aggressively. Cornering them, pushing them, nipping their fins. Separated him too. The next morning I found one of my Orandas dead. His fins scales everything was gone…. Body was almost white. And the sucker was stuck to it. I also noticed that the other Oranda has white spots on his tail. Please help. What is causing all this carnage in my tank. When I went to the pet store, they found it amusing that the tetras fin-nipped the goldfish, but my husband and I saw it with our own eyes. Several times. What do I do ? Why did it die ? And did the other fish eat the body ? How do I stop the attacking ? Please help.

  26. **NeonGlitter** on said:

    Hi, I bought two small goldfish today. I bought them from one of them stalls you get at fairs where you do darts etc to win a goldfish. I'm worried it's already sick because I've heard they're treated badly before going onto the stall. Is there any way I can do a health check?I am 11 and your blog has been very usful to me.

  27. Janet on said:

    Hi Jamie,I have 2 fantail gold fish in a 29 gallon tank, i have had them both almost 3 years, the smaller one got stuck in the castle hole and now has many scales missing and his beautiful tail on one side is shredded, i noticed the sucker fish was after him after this and i removed him from the tank to another tank, i am using melafix and quick cure daily, this happened 2 days ago and i am also doing a partial tank change daily. he stays at the bottom afloat, eats well do you think he has a change of recovering, i also use aquarium salt in the tank and always have, i am worried this is going to affect my attempts to prevent infection. is there anything else i should do or not do? Thank You

  28. Anonymous on said:

    My fantail goldfish is rather large and I have come to relize that he has a scale that is loose or starting to come out, but the problem i am seeing just recently Is that the scale is starting to turn blackish, underneth it. He has had the loose scale for a while, but like I said, it seems to be having black stuff under it, i just hope its not something life threatning to him. I know losing scales is normal but the black stuff seems wrong, Please help and I am sorry this was kind of random.-Shanep.s he is almost a year in a half old.

  29. Anonymous on said:

    Hi, I've had several gold fish for a classroom pond for 7 years – bringing them home to 10 gal. aquarium during the summer. One goldfish with the most beautiful flowing long tail has one side that is shredding? (Following our installation of a home water softening system – although I have put water in aquarium using only the unsoftened cold water tap along with Tetra Pond water conditioner. Both gold fish are about 5-6 inches not including tails are also loosing scales. Have read blogs, but not certain if medication might be needed or know how I test water condition. All other aquarium fish – same buddies for last 5-7 years are fine. Thanks much for your thoughts.Deb

  30. Anonymous on said:

    Hey Fishman,My names Brian. I've been on your website a few times when I've had problems and thanks a bunch. But now I have a bubble-eyed goldfish (don't know the proper name) that has tail rot. From what I've read online, most tail rot appears reddish-pink? Well my fish's tail is black on the end in places and it has a white spot or two on it's head. I've been using Melafix for a few days in my 10 gal. tank, but just learned I can't keep my carbon in it at the same time. I just quarantined it in a small fishbowl, put Prime water treatment to remove Nitrates etc. and a few drops of Melafix. It hasn't been eating and sitting at the bottom, so I put a few flakes in front of it and it just chews it up and spits it out. HELP PLLLZZZ!!!

  31. Anonymous on said:

    Hi Jamie Well I have recently bought some goldfish and I have use drinking water instead of tap water. And everything was ok till about a couple of days ago when one of my goldfish tail was rottening I thought he had something stuck to his tail to I tryed to take it off which was bad idea. So I seperated him from the rest. But he died. So just the other day I noticed that my black moores tail was doing the same so I got online and read of how to cure it but all it said was to buy a water purifying bottle to clean the water from any bacteria. I bought Stress Zyme Aquarium start & clean Dual action bacteria & also I bought Quick cure fast relief for Ick & protozoan parasites.I dont know If I should mix them to try and cure my black moore..? what do I do?

  32. Jonny Nates on said:

    Hi my gold fish has Tail Rot. i live in South Africa so i don't think i can get the medicine you suggested. So far i am using this (Koi and Goldfish Special by Rid-All)I don't know if it will help please tell me soon I REALLY DON'T WANT MY FISH TO DIE D:

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