# Help Diagnosing Severum Skin Lesion



## Frogs 'n' Things (Apr 21, 2012)

Hi All,
Anyone have ideas on what might be causing this on one of my severums? There is also a silver doller with similar lesions. The other fish (even same species) see fine. Lesions have been present for ~4m, and don't seem to bother the fish. But they are slowly growing and showing up in more places. I've tried treating with formalyine/malachite green, triple sulfa, and victoria green/acriflavine. None of those seem to help. I hate treating blindly, but can't seem to track down the cause online. Any help would be appreciated.
Thanks,
Keith


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## susankat (Nov 15, 2008)

Need some answers first.

Size of tank?
How many fish in tank?
How long has tank been running? How long has fish been in tank?
parameters? Numbers not just fine or good.
Ammonia?
Nitrites?
Nitrates?
Ph?


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## Frogs 'n' Things (Apr 21, 2012)

Ro/di h20 reconst to 100 ppm GH and KH
7.0 pH. 78F. NH3 nitrites nitrates undetected. 
45g running 15+yrs. Currently 10 2-5in fish. 
The other larger severum injures himself frequently and it clears in a week. This one won't heal and it did not start as an injury. Spreading to multiple sites but not to others fish. 
Thanks.


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## susankat (Nov 15, 2008)

Whats ammonia? Do you have a lot of plants in the tank?


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## Frogs 'n' Things (Apr 21, 2012)

susankat said:


> Whats ammonia? Do you have a lot of plants in the tank?


Ammonia (Nh3) is undetectable. No live plants.


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## susankat (Nov 15, 2008)

That don't sound right, are you using strips or liquid. With no plants you should be showing nitates. Strips are unreliable.


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## snail (Aug 6, 2010)

I agree, it is impossible to have 0 nitrates in a mature unplanted tank.

Are there scales missing on the effected areas?


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## Frogs 'n' Things (Apr 21, 2012)

snail said:


> I agree, it is impossible to have 0 nitrates in a mature unplanted tank.
> 
> Are there scales missing on the effected areas?


Well, I agree. Nitrates are low, but that's what they run in my tank. I tested again, API fw/sw kit. Maybe a hint of color but <5ppm. Maybe the algea eats it up?
At any rate, doesn't seem like this would explain the source of the lesions.
Scales are missing from the center of worst lesions (in pic). Scales raised on the periphery.
I appreciate the feedback.
Keith


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## susankat (Nov 15, 2008)

It can be many things. Are you sure they aren't showing any aggression? As it may have started out as an injury and gotten worse. It could also started out as a burn from the heater. 

How much algea do you have in the tank? It would take a bit to keep nitrates that low.


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## snail (Aug 6, 2010)

I was thinking it looks like a heater burn but it seems unlikely that multiple fish would burn themselves in multiple places at the same time.

How often and how much do you do for water changes?


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## Frogs 'n' Things (Apr 21, 2012)

Yes, I thought it was an injury at 1st, but w/ secondary spots showing up (that don't look like injuries) I'm thinking there is something else goining on. The heater is pretty well buried behind a pile of rocks - I don't think they get back there. There is some agression, and actually the big severum is crazy and scrapes his scales off all the time. They heal up real quick - another reason I'm thinking this is more than just an injury.
I change the 20% of the H20 every other week.
Keith


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## navigator black (Jan 3, 2012)

It looks bacterial. The most common bacteria to produce lesions like that is Mycobacter marinum, but suggesting that is a possibility makes you very unpopular in aquarium circles.
Scales raised on the periphery and the placement of the sores, alongside the lateral line are not good things. Wear gloves and never expose an open cut to the water as a precaution. If it is M. marinum, it is fatal to fish, and in rare cases, transferable as a slow to cure but curable annoyance to humans.


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## Frogs 'n' Things (Apr 21, 2012)

Nice! Should it have responded to triple sulfa? Other preferred antibiotic?
Thanks


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## snail (Aug 6, 2010)

Not saying it's the problem but you might want to get another test for nitrates. Low nitrates in an unplanted tank could make sense with large water changes but I can't see how it's possible with 20% every 2 weeks unless there is a huge amount of algae in there.


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## snail (Aug 6, 2010)

navigator black said:


> It looks bacterial. The most common bacteria to produce lesions like that is Mycobacter marinum, but suggesting that is a possibility makes you very unpopular in aquarium circles.
> Scales raised on the periphery and the placement of the sores, alongside the lateral line are not good things. Wear gloves and never expose an open cut to the water as a precaution. If it is M. marinum, it is fatal to fish, and in rare cases, transferable as a slow to cure but curable annoyance to humans.


navigator black- I think it wasn't that you suggested MB that got people going but that you advised fairly drastic measures without having much to diagnose by, people thought it was a bit of an overreaction. Don't get me wrong I think you generally give very good advice and I value your experience. In fact if we all had the experience you did with MB we might feel differently .

It does seem like MB should be considered in this case. Have fish shown any other symptoms like wasting?


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## navigator black (Jan 3, 2012)

I have read people suggesting the use of UV on marinum and claiming a cure - I'm skeptical because the even the large public aquariums can't solve it. It would not have responded to triple sulfa. It can survive bleach. In human cases (I caught it) it takes six months of two antibiotics - ten pills a day to take it down. It is a tough bacteria. We aren't even a good home for it and it can hang on that doggedly.

Snail - the time you refer to I admit, my cure was to euthanize. But on other forums with fairly obvious cases, I've suggested marinum with no measures offered, and been ripped for saying the name. It's a bit like saying the name of Voldemort. ;-)

It's a very common bacteria in tanks, on farms and in public aquariums - the places where they test for these things. Fish seem to fight it off, except when stressed or old. Some species get it easily. And transfers to people are rare - I learned about it by being one of the few.


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## snail (Aug 6, 2010)

lol, we do tend to resist bad news


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## Frogs 'n' Things (Apr 21, 2012)

snail said:


> lol, we do tend to resist bad news


LOL - that's why I started the post in the 1st place - I was hoping to hear "that looks like parasite x treat with y". I guess I should have known MB was the most obvious answer - especially given the slow growth, presense on only 1-2 fish, and lack of response to short term antibiotic.

Per my avator, I'm an avid dart frog hobbiest and breeder. MB is the V-word in that hobby as well. I heard of many cases were prized collections have been euthanized after a + MB test. Also often hear MB blamed for sudden death of enitre dart frog collections. Neither makes much sense at all to me. This is a very slow growing ubiquitous class of bacteria that is very common including in many of our faucets. If it were as infectious and deadly as perceived, noone would have healthy dart frog collections. I suspect its present to some degree in most terrariums and aquariums (even if tests come back negative). Don't get me wrong, its not a nice bug - especially given its resistance to treatment and ability to infect humans. But, a postive MB test, and even resultant death of a specimen does not mean certain doom for the rest of the collection. Its an opportunistic parasite, so will often infect skin abrasions on frogs but the initial cause was probably injury. Best antidote is a clean tank and avoiding abraisions. And don't forget to wash your hands after being in a tank - salmonella is just as common in the terrarium and much more dagerous human parasite!
OK, that's my 2 cents.

Frogs are very sussecptible to infection upon injury. I've had very good success with tripple sulfa at least stopping spread if not healing skin infections. I don't know how many of the infections were MB, but its likely some were.

I think I'll try another course of antibiotics just to see if it helps my poor severum any. Dox is the reccomended tmt for humans, so I'll give that a try.

Thanks again all for your input and advice.
Keith


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## snail (Aug 6, 2010)

I tend to agree that often MB is opportune,taking advantage of a weakness rather than always being the primary cause. Perhaps some strains are more aggressive than others though. Hope it works out. Please keep us posted, I'm interested to know your progress.


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## navigator black (Jan 3, 2012)

You know, in the end, after ages of antibiotics, the thing that got rid of the last lesion on my hand was heat packs inside a glove. 
There was apparently a serious danger of that causing scars, but my hands ain't pretty anyway so I went for it. I had given up the hand model dream already, and there are no scars.
It's too bad you couldn't take the tank up to 40c (104f) for a few days, with lots of aeration. If the heat didn't kill the fish, you might save it. The bacteria were only able to survive on the outer layer of my skin, up the lymphatic system, because internally, it was way too hot for them. It's a skin surface problem in humans. 
So the bacteria were already struggling at 37 degrees celsius... really hot but...
I guess it would kill the fish, but so will marinum. You could be the only hobbyist who ever set out to find a stuck heater.


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## snail (Aug 6, 2010)

From my experience with hot summer weather fish can take it hotter than you'd think as long as they have enough oxygen. 40 might be pushing it but then I know my house has been over 40 and I thought I might die but the fish were fine . Of course the tank temperature would not be as hot as that in the tank but next time I have to see how hot it gets. I do avoid keeping fish that are sensitive to heat.


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