Fishkeeper's Granuloma - Mycobacteriosis

Fox46 · Mar 11, 2026

Three months ago I developed a boil/carbuncle on my thumb which lingered for ages. Then it burst but didn't fully resolve, leaving a slightly larger flatter swelling. Then the area developed little pustules/blisters and I tried various ointments to draw them out. Eventually I saw some suspicious discolouration near my wrist and having had the symptoms of granuloma in my mind for some weeks, I went to the doctor. The definitive test for Mycobacteriosis is a complicated, expensive affair, he tells me. I'd have to go to a special unit to have a culture taken, it has to be frozen immediately and couriered to a special centre for testing and it can take a long time to process. I'm now on a massive dose of strong antibiotics for a month before reviewing the situation, and have been warned I may have to stay on them for up to 3 months. If it hasn't resolved after that, then I guess the special procedure will be initiated. I've run several tanks for seven years or so, and have been reasonably careful when cleaning etc. but I haven't usually worn gloves unless I'm aware of a particular cut/scratch or wound on my hands and arms, in which case I've been ultra careful, applying waterproof plasters, and using rubber gloves . But there are some things you have to do in the tank where protective gloves just won't permit the degree of precision required or you have to take a swift action when a fish gets trapped etc.
Of course, this issue may respond to the antibiotics I'm taking (with all their side-effects

) but having had time now to review my approach to tank maintenance, I thought I'd post this just as a warning to others. I took precautions when I knew I had cuts that put me at risk, but it may turn out that that wasn't enough.

TwoTankAmin · Mar 11, 2026

I used to have a big problem with dry skin. I would actually lose a complete layer of skin om my palms and most of my fingers. I came up with a solution involving gloves. I am also allergic to nitrate. So squeezing our foam media was a particular problem. I have the aqua gloved which come right up to one's armpits. The problem with there are the actual glove part is so thick it impedes one's ability to do any kind of fine work when wearing them. I tried dish gloves and wound up with water filled gloves so that was no help.

Coralife Aqua Gloves

https://www.coralifeproducts.com/all-products/specialty-equipment/aqua-gloves

What I came up with was a combination of waterproof tape and exam gloves. I would use three pieces of tape to seal the gloves above the wrist. The first strip of tape was applied 1/2 to the glove edge and one half on my arm. The to get a good seal I added two more strips of tape. One reinforced the tape connection to the arm and other went one the opposite side and secured the glove and the initial piece of tape.

This pretty much sealed in the hand. But there are some things that need a clear ungloved hand to do. This is especially the case if one has to handle Scotch or any other form of sticky tape. If using the gloved hand, the tape will stick to the glove and often tear the glove trying to unstick it. So for the other hand I used a dish glove which was easy to put one and take off if I needed to do so. Also if I had to reach into a deeper tank I could always use my left hand (the right was sealed in the exam glove as I am right handed). I would put on the long Aqua glove for this.

However, because i had a number of pleco species tanks fore spawning and growing out, these were shallower tanks- 33L and 20L. In thiese tanks I found anther way to go. There are longer style dis gloved with an elastic top. East to put on and take off with dry hands. I could uses these gloves for working in the shallower tanks. The one caveat is if you reach into a tank at to much of an angle, you can inadvertently submerge the elastic top of the glove and the elastic does not seal it. I had to learn to avoid making this mistake.

I searched Amazon for longer dish gloves and found what I needed:

3 Pairs Reusable Long Sleeve Durable Gloves PVC Vinyl Household Cleaning Anti Allergic Large Adult Size

I have them in blue, green and pink. I keep a few pairs in both our buildings where I have tanks. The above are good for going into the water up to the start of the elbow and not above.

I really needed the gloves when I had 20 tanks. Today I am down to 12 tanks and one of these is only plants. All but 3 tanks are now well planted which means nitrate levels tend to be lower or close to 0. Plants use nitrates. With the reduce number my jands are spending much less time submerged in tank water.

Incidentally dry skin on my hands makes using touch screen difficult for me. I touch the screen and nothing happens most of the time. So, I do not use or own a smart phone or tablet. Add to this that I hate smaller screens, so, I do not use nor own a smart phone or tablet.

Fox46 · Mar 12, 2026

Those long gloves with elasticated tops look useful. I've a stock of disposable plastic arm-lengths but even though I've switched to shallow tanks they still allow the water in over the tops. Thanks.

MattW · Mar 12, 2026

I've been using disposable gloves on my tanks for 2 or so years now. I did have a breakout of TB in a fry tank, which caused a lot of fry to become deformed or end up dead. I am prone to cuts on the hands because of my job, so I don't want to run any risk. If I do have to go arms-length into the tank to clean my powerhead, for example, I will thoroughly wash fingers, hands and arms with hot soapy water. Then, hand sanitiser on any cuts or areas of concern. The lady who runs the local pet shop contracted Mycobacteriosis after cleaning out one of the shop tanks. She showed me some pics of the infection making its way up her arm (not a pleasant thing at all). Thankfully, the GP recognised what it was quite quickly. The antibiotics she was on helped a lot, which was also around 3 months worth.

These are a pair I have been contemplating when my disposable ones run out.

Velda Pond Gloves 60cm | Waterproof Arm Protection

Velda Pond Gloves: 60cm waterproof protection for hands and arms. Durable PVC with non-slip grip. Elasticated cuff keeps water out. Ideal for ponds & drainage tasks.

aquacadabra.com

Rusty_Shackleford · Mar 12, 2026

This is something I'm conscious of, though I don't wear gloves. My first rule is always to avoid sticking my hands in an aquarium unless it's absolutely necessary.
A few weeks ago when I burned my hand I made an effort to not stick that hand in am aquarium.

Fox46 · Mar 12, 2026

I've been remiss. I knew about the risks, especially with owning a temperamental sharp-clawed cat who can leave me battle-scarred after a pill-giving. I won't slip up again though, hopefully. The antibiotics are the size of the old liquorice torpedoes and by the time I've finished using a pill-cutter to reduce them to an acceptable size, my husband says it looks like I've been doing several lines of coke on the kitchen counter. Thanks for the tips re the different types of gloves.

Magnum Man · Mar 12, 2026

I do get my hands wet, but keep a various tool kit here, so I don’t go usually any deeper than my wrist… it’s still a potential, but so is doing anything in the local lakes

GaryE · Mar 14, 2026

When I caught fish tb (I have luck like that) I had six months of several antibiotics.

I had it on the back of my hand and it was slowly moving up aiming for the armpits. I used handwarmers in a glove once daily, and it can't take warmth. You can cause scarring by doing this, but no one's going to hire me as a hand model so this risk didn't worry me. I feel that it accelerated the wiping out of the pathogen.

Fox46 · Mar 15, 2026

GaryE said:
When I caught fish tb (I have luck like that) I had six months of several antibiotics.

I had it on the back of my hand and it was slowly moving up aiming for the armpits. I used handwarmers in a glove once daily, and it can't take warmth. You can cause scarring by doing this, but no one's going to hire me as a hand model so this risk didn't worry me. I feel that it accelerated the wiping out of the pathogen.

Might try the handwarmers. six months sounds dreadful. I'm only 2 weeks into the antibiotics and already have uncomfortable side effects. Did your doctor diagnose it straight away? I was fairly sure I knew what it was before I saw the doc and he immediately confirmed and went straight for the recommended strong antibiotic. Some doctors start with a general antibiotic and then keep switching to ever stronger antibiotics until the right one works. Mine is on the inside of the thumb but when 2 discoloured patches emerged on my wrist I decided I wouldn't wait any longer and made an appointment.

Naughts · Mar 15, 2026

What does/did the lesion look like? Will you close your tank down?

GaryE · Mar 15, 2026

My GP didn't recognize it, and my dermatologist was looking like he almost knew until I suggested Mycobacter marinum. We established it right away. The treatment was a cocktail of older antibiotics - if I recall correctly, 3. This was 25 years ago though. It made a mess of my guts for months.

It seems better known as a problem of scuba divers, and from unchlorinated cement pools.

My lesions (3) traveling along the lymphatic system were rectangular and raised - very hard. They never burst. They were exactly as the disease presents on the flanks of a rainbowfish - the same shape although I'm not as vividly coloured as my rainbows were...

The heat idea was easy since it was Canadian winter so one gloved me didn't look like a Michael Jackson imitator who hadn't learned about the man's life. I was told that if I overdid it (my doctor did not suggest it and thought I should be more patient) I could get a red spidered scar several cm in size radiating out from the original lesion. By the time I discovered the idea of warmth from an old fishkeeping discussion, I was down to one persistent lesion. I have a small scar from the biopsy and a mark where one lesion was, but they just fit in with the many small injuries I've done to my hands over the years.

I would get a general checkup. I lived in a city of 3 million and saw a teaching doctor of dermatology at a major university. I was the first case he had seen. At the time, I was juggling 2 jobs, a young family and care for a dying family member, and for many months was sleeping 4 or 5 hours a night. I was in a state of chronic exhaustion, and my immune system was not up to where it should have been. I doubt I would have caught Myco if I had been as I am now - rested and healthier.

I've since seen an untreated person - a fish store employee with a drug problem running her down, and you don't want to leave it. What the treatment does is unpleasant, but when the sores get to the armpits - nooooo. You do not want that!

Here's a pleasant thought. If at any time in my life I am tested for the human form of tuberculosis, I will test positive because of my antibodies.

I still keep fish. I still take great enjoyment from my hobby. You should see the thing you get from garden soil, or the bones I broke playing sports etc. It's a statistical risk, but a very unlikely one. You and I just have a certain kind of luck.

AJ356 · Mar 15, 2026

Thanks for posting. I've never used gloves in about 15 years of keeping fish. My hands are always in the tanks, even if I have a cut, which is quite frequently with my clumsyness. And I am also one of those people who still manually suck to siphon water out the tank. Maybe one day it will all catch up with me, or maybe it won't. Worth knowing about.

Fox46 · Mar 15, 2026

The lesion had the appearance of a boil or carbuncle, and I noticed it in December. It formed a head but stayed like that for a month before partial bursting. Then the area around it hardened into a lump under the lesion and I would notice small pus-filled blisters forming on that outer area, whilst the boil/carbuncle thing remained pretty much the same but without a head. I tried wearing a plaster with Magnesium Sulphate paste on it, to draw it, and though it was mildly effective, it still didn't go away. When I noticed a discoloured patch forming on my wrist I decided to act. I've been on the antibiotics for just short of two weeks and I'm pretty sure the hard lump (which was about the size of a kidney bean, has reduced to the size of a small pea. The central part is not as red it seems, but that might be wishful thinking.
No, I won't give up fishkeeping. But I've just done the most frustrating water change of my life with my waterproof-plastered thumb encased in surgical gloves then encased in ginormous up-to-my-elbow Marigolds. I couldn't retrieve errant suction cups from the glass, couldn't place them back, could barely open the filters to get the sponges out... So I might leave the second tank until tomorrow for its water change.

Fox46 · Mar 15, 2026

In addition to the heat treatment which I was just reading about, I believe vinegar is also effective in killing this bacteria. So I'm off to sit with my thumb in a cup of vinegar for 20 minutes.

TwoTankAmin · Mar 15, 2026

My problem is only been dry skin and the nitrate issue. Because my pleco breeding tanks contained no plants, they were likely to have nitrate in them. However, the Mattenfilter tanks seem to develop denitrification pockets.

When I had 20- tanks year round and then 5-8 more over the summer, I had to work on all of them weekly. I had to use gloves. However, since I have been downsizing I am now at 12 tanks one of which is all plants and a few snails but no fish. So I have 3 tanks without plants. I also have fewer gallons per tank.

I have stopped wearing gloves as a result. I am having almost no problems. The one exception is that I may put on a glove to squeeze out the AquaClear foams. The Poret one I only swish. So every now and then t get a small dry patch.

Over the years I have had bare hands and arms in tanks at least part time. I have never had any issues besides the dry skin. A number of years ago I sliced my hand in a non-aquarium related incident involving a supermarket shopping cart. I went to the local urgent care and they cleaned it and stitched it up. But it still got badly infected and this spread. So I hit the ER. I wound up as an in-patient on an IV cocktail of 3 meds for 2.5 days. One of them was Metronidazole which I keep in my fish med kit.

The docs wanted me on an oral antibiotic, but is was one I usually wont take as it really upsets my stomach and gives me awful headaches, However, It is not an issue when delivered as an IV. So for the next two weeks I had to have a daily IV infusion of an antibiotic. Fortunately, I have no issues with needles. I am very lucky to live about 5 minutes from a major medical practice which I have used for almost 40 yeras and we have an excellent local hospital as well. And what they cannot handle there are two bigger hospitals available within a 20 minute drive.

It is important with most medical problems to see a doctor. Hopefully, they will be helpful more often than not.