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Do fish get Melanoma?

chriscoli

Administrator
I've got two fish that are displaying patches of very slowly growing discolorations on their bodies, but mostly at the bases of their fins. In some places the body seems to be eroding a little around the areas. There's no redness or open sores, although one lost (or had it picked off) a pectoral fin in one of the worst areas.

Whatever it is it's very slowly spreading and doesn't seem to be affecting any other than these two fish.

I've had them isolated and have been keeping an eye on them to see if anything else happens.

So, part of me is wondering if this could be a type of cancer. Anyone else seen this in their fish?

Below are two pics of the same fish...

melanoma 1-0675.jpg

melanoma 2-0678.jpg
 

neut

Members
Fish can get skin cancer, but from what I've read this would take intense sun exposure, like in a shallow and unshaded pond in a hot climate. I'd be more inclined to think along the lines of early stages of a fungal or bacterial infection, maybe columnaris? (unlike some infections that you might think poor water quality, columnaris actually likes clean, well oxygenated conditions)

If just one species of fish is getting it but others are ok, it's possible it indicates conditions (ph or temperature, for example) they're not comfortable in. Had something like that happen with guianacara once, ph inadvertently went high and the other eartheaters were fine, but the guinanacara were coming down with fungus issues.
 

dogofwar

CCA Members
They do..there's great research on this, especially with Poecilids back to the 1930's (Dr. Myron Gordon and others).

Given that they're the Etroplus, I've heard that they like a cool down period. I know that Gymnogeos that don't get cool downs experience all sorts of weird symptoms and disease (although nothing like that)...

Matt
 

chriscoli

Administrator
Fish can get skin cancer, but from what I've read this would take intense sun exposure, like in a shallow and unshaded pond in a hot climate. I'd be more inclined to think along the lines of early stages of a fungal or bacterial infection, maybe columnaris? (unlike some infections that you might think poor water quality, columnaris actually likes clean, well oxygenated conditions)

If just one species of fish is getting it but others are ok, it's possible it indicates conditions (ph or temperature, for example) they're not comfortable in. Had something like that happen with guianacara once, ph inadvertently went high and the other eartheaters were fine, but the guinanacara were coming down with fungus issues.


I had also considered bacterial/fungal but it's not manifesting like anything I've seen. Definitely haven't ruled them out. There's no slimed or cottony appearance on the outside of the fish. Whatever's happening is going on at the skin and muscle level.

Pimafix/melafix don't touch it. Since I had another fish with a bacterial infection I needed to treat anyway, they got a round of Kanaplex.....I was worried about secondary infection to whatever it was.

So, maybe back to the basics with salt or methylene blue dips, or onward to fungal treatments.
 

chriscoli

Administrator
They do..there's great research on this, especially with Poecilids back to the 1930's (Dr. Myron Gordon and others).

Given that they're the Etroplus, I've heard that they like a cool down period. I know that Gymnogeos that don't get cool downs experience all sorts of weird symptoms and disease (although nothing like that)...

Matt

From what I've heard, most Etroplus canarensis do fine in average tank conditions until you want them to spawn.....that's when the cool down is critical. The Texas breeders are even keeping them in uber hard water which is not typical of their habitat.

Since I don't have a proper fishroom that can be isolated from the rest of the house, I tend to keep my tanks on the cool side so I don't break the bank too much with the electric bill. In general, my stuff is all kept in the 72 to 76 range with only a few exceptions for fish that need more. Not that this constitutes a cool down, but I'm not keeping them at 80 either.
 

neut

Members
I had also considered bacterial/fungal but it's not manifesting like anything I've seen. Definitely haven't ruled them out. There's no slimed or cottony appearance on the outside of the fish. Whatever's happening is going on at the skin and muscle level.
Don't want to be alarmist, here, and it's getting outside anything I have experience with, so I wouldn't attempt to diagnose it, but your comment made me think of the possibility of mycobacterium (fish TB). I could be way off, and Kanamycin is supposed to be a possible treatment, but the thing of it is, if it's anything like that, you need to be careful because it can be transmitted to humans. I've only ever known of one person to actually get it, but imo it's worth some extra caution handling a fish with something unusual/unknown that's not responding to garden variety meds.

Again, don't want to be alarmist and not saying it's your problem, just something that came to mind when you said it's unlike anything you've seen before. But it's worth at least knowing something about it, both for you and your fish, so here's a starter link with some basics.
 
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chriscoli

Administrator
Yep, definitely aware of the possibility of Mycobacterium. I'm not convinced yet that the symptoms match at this point, although it can manifest a wide variety of symptoms so it's not an impossibility.
 

neut

Members
Another malady with which I don't have personal experience, supposedly fairly common and supposedly rarely lethal, but also infectious (if I understand and remember, the nodules break and release more virus after which the individual fish can heal). Main thing I've seen is photos of fish having the bumps or nodules. The other thing I've read is since there are multiple strains of the virus, it might affect one species or closely related species, but not necessarily affect other fish.

Might sound weird, but I've just recently done a little reading on this natural fish treatment from a lichen, apparently pretty broad spectrum, and when I looked at it again, the article mentions both fish TB and lymphocystis. (author, Strohmeyer, has many years in aquarium maintenance business, has done a lot of research, has a web site that goes into different meds and what they do, etc.)

I'd just add the disclaimer that as far as I know this would be a little avant garde and I've yet to hear much of anything of other fishkeepers using it or commenting on it.
 
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