A Closer Look at Tail and Fin Rot – Part 1 (Symptoms & Causes)
Tail and fin rot is is an easily recognizable, and very common fish disease. It occurs in aquariums, ponds, fish farms and the wild – both in rivers and in oceans.
It is a serious fish disease that can eat into the body of the fish after destroying all of a fin, leading to death. Even before it gets to that stage, it can lead to severe complications. Very often, a fungal infection takes hold in the affected fin, making treatment even more problematic.
Symptoms
The first signs of tail and fin rot are red streaks in the fins. The edge of the fin will then lighten, before it starts to rot away and gain a ragged appearance. Small bleeds may also be present.
Biological symptoms include variations in the levels of calcium and haemoglobin in the fish’s blood.
If a fungal infection occurs, the edge of the fin may be smoother i.e. get eaten away in a more uniform manner – and have a white edge.
Causes
Tail and fin rot is caused by bacteria. The specific bacteria that cause the disease are common and found in most bodies of water, including ponds and aquariums. The problem arises when the fish are subjected to an external event or environment that make them susceptible to infection.
By far the most common factors are poor water quality (especially raised levels of ammonia and nitrite), and direct trauma to the tail and/or fins. Direct trauma can be a result of nipping by other fish, bad handling by humans, or sharp edges on plants and ornaments in the water. The stress of any of these events leaves the fish open to infection.
There are three different bacteria that can cause tail and fin rot:
- Aeromonas – a rod shaped bacterium that can also infect humans, often resulting in the need for amputation.
- Pseudomonas – another rod shaped bacterium that has “superbug” strains found in hospitals that cause necrotizing inflammation in humans.
- Flexibacter – a bacteria that normally only affects fish, and is best known for strains that are bright yellow to the naked eye when colonies grow large enough.
To be precise, tail and fin rot is not a disease itself. It is actually just a symptom of infection with one of these bacteria.
What the bacteria do is congregate in the intestine of the fish. They then produce a mucous that contains molecules that are toxic to fish. These toxic substances are absorbed through the wall of the intestine in much the same manner as essential nutrients, thereby entering the bloodstream.
The red streaks that are the first sign of tail and fin rot are caused by small blood vessels in the fins breaking apart under the action of the poison, and releasing blood.
Without a blood supply, the fins quickly lose their colour, break down and rot away.
While all this is happening on the outside of the fish, similar processes are destroying the blood vessels of the stomach, liver and kidney.
January 16th, 2009 at 9:46 am
can anybody help?
we have 9 goldfish in a 78 litre tank.. one of the fish has tail rot.. his fins were clamped for a few days and today his tail has rotted and is white..
the tank is cleaned often and has plastic plants and one ornament, bubble snake and lights on about 8 hours a day. no hidey holes.
water was changed yesterday and pH level today was in high sevens – am bring the pH down as we speak..
are the other fish at risk of being infected? he is too far gone to save?
thanks for any help
January 23rd, 2009 at 10:56 pm
I have the same problem with a ryukin goldfish I bought a week ago.
I’ve had two shubunkin, one is five, the other is 7 months and already 6 inches long.
I have a Marineland tank with the BioWheel filter which they say never needs to be replaced, but it looked really grimy and I almost replaced it before putting the new fish in. Now I wonder if I should have.
I just went to the pet store and got Maracyn and started treatment. I’m also moving the tank into the bathroom which is warmer; it’s been in the 20s and teens here lately and while my older fish doesn’t mind cooler water, this guy was in a really warm fish room and the change in temps may have been bad for his immune system.
He’s got, or had, a beautiful fantail and it was fine as of two days ago when I was showing him to a friend, but this morning he was sitting on the bottom and when I fed him and he swam upward I saw he’s missing half his tail (he’s a very small fish, not even 2 inches.) He can still swim but doesn’t except when feeding.
I just did a 1/3 water change yesterday, but the water already looks a little cloudy; again, I’m wondering about the BioWheel. Plus with Maracyn you have to remove the carbon from the filter, which means less goldfish poop getting filtered, and this ryukin is even poopier than my shubys were at the same size.
Luckily he’s in a starter tank, I always put new fish in there to protect my other fish. When I first started with fish I lost two little goldfish to fin rot within a few days of getting them, but the first one was dead before I noticed the fin rot because their fins were transparent and it was too late to save the other who died the next day. This one has a mostly black tail so it was really noticeable that it was rotting off.
I’m hoping to save him with the Maracyn, water change again tomorrow before I put in the second dose, raising the tank temperature. I even bought him a new kind of food, I asked the pet store what they had been feeding him and got that (I’d been giving him flakes, which my shubys love, but they’d been feeding pellets.)
Some sites say to try Melafix first, but I figure if he’s lost half his tail in two days it calls for tough measures.
You are doing all the right things but you may need antibiotics. My fish dealer recommended the Mardel line (Maracyn etc.)
Hope our fishies make it!
June 4th, 2009 at 9:27 pm
Hi, I’ve had a goldfish for 6 years and it belonged to another owner for a number of years beforehand so I am led to believe he is quite old. A few months ago I noticed that one of his fine was a lot smaller than the other (about the size of a pinky finger nail) whereas the the larger is about the size of half a pinky finger. But when cleaning him out the other day I noticed that bits of his tail had disappeared, looking as if they had been ripped off; tail and fin rot is the closest match I can find. He used to live with another goldfish who died a few years ago so he is now single who admittedly I do not clean out as often as I should but still fairly frequently. Is this tail and fin rot? I’m 14 so I have no idea how to check for the pH of water or what would help him.
Please please help I love this fish so much and I hate to think that I might be losing him.
September 2nd, 2009 at 1:38 pm
hi i also have a gold fish with fin rot .i am only twelve and me and my dad went to our local water gardens we got a medicen specified for fin rot .we also got some water condishener and mixed them with clean water and put that water in the fish tank.if this is any help to you
September 7th, 2009 at 6:32 am
if you are suspecting fin rot, it’s maybe because of poor water quality. buy a freshwater test kit (or 3-in-1 test strips, cheaper) to measure ammonia, nitrite, nitrate and PH. ammonia and nitrite should be 0, you might get faint nitrate which is ok, PH can be 7.1-7.6 for goldfish. if ammonia and nitrite levels are higher, do a 30% partial water change every day for 4 days. then measure it again.
is your tank properly cycled? please read up on nitrogen cycle in fish tanks. adding extra water conditioner helps with stress relieving, but don’t think it works for fin rot. your water conditioner should be used for removing chlorine from tap water, that you put in your fish tank. never, never put tap water in tank BEFORE adding water conditioner in it. for partial water changes, let the water age for a day or two before adding it to tank.
September 16th, 2009 at 5:50 am
Hi
I got a goldfish from the fair
i clean his water all the time and feed him properly. he has alot of room, and his water has a lot of surface for absorbing oxygen.
he has black steaks in his tail and they were not there when i got him. I dont know if this is a disease or his ccoloring, but if it is, i want to make sure, so i can treat him.
Thanks
Lauren
October 25th, 2009 at 5:11 pm
Hi, I got two fish in August. One of them died about two weeks late. What was weird was
that this fish did not float he sank. I know he was dead cause he would’nt wake up.
Is that normal? For a fish to sink like that?
My second fish I could tell was quite disappointed, he would lay next to the dead one until we took him out.
Now this same fish (the alive one who’s name is Fishy) for the past week has been acting strange.
I thought at first he was lonely. Then he started not moving all day and just being active at night.
He was okay at first staying up all night being asleep all day until he just stopped moving.
He would move corner to corner but never swam around like he used to.
I am really worried, he won’t even go to the surface to eat.
He stays at the bottom all the time.
I noticed last week that he was going a little white on his fins. I thought it was just his color.
Today I woke up and noticed that he had this kind of white stuff, I have no clue how to discribe it,
over parts of his fins, over the top of his eyes, and a bit on his sides. Its like some kind of white
sorta gelly almost fluffy-ish looking stuff. My mom had this book that I quickly looked at. When I read about the diseases none of them really matched. The Fin rot was the closest thing in the book so I decided to look it up. It does not really look like the fin rot. Any ideas what it is or what I could do to help poor fishy?
Hope you can help me,
Emily
November 23rd, 2009 at 5:44 am
for your fish with the white fluffy ish looking stuff on his fins and eyes, get this stuff to treat it. its called Ick. Salt will help cure most of anything, but if the salt dont work, get the Ick. It is supposed to take the bad stuff off of his fins and put back the good bacteria. Hope this helps you.
February 1st, 2010 at 5:46 pm
its really strange, I had four fish, Bill, Ben Red and Speckles, Id had Bill and Ben around 2 years and put the other 2 in and all of a sudden Ben died, then Bill
but red and Speckles are absolutely fine! noticed about 2 days ago red’s fins were shredding, but I got up the next day and they were back to normal!! can anyone explain how the hec he’s fixed himself so quickly????
February 27th, 2010 at 11:55 am
One of my goldfish has black streaks on it’s fins too.