# Black spots on fish



## QueticoMike (Sep 25, 2008)

This is all I could find on the black spots on fish, don't know if this is the same reason the smallmouth have these black spots or not. I've heard some people call it " ich " before, but I believe that is only for salt water fish.....

Black spots

Black spot disease is commonly observed in rock bass and other sunfish, bass, pike, perch, minnows, and other fish species. It can be identified by the presence of small black spots, usually about the size of a pin head, in the skin, the fins, the musculature, and the mouth of the fish. The black spots are caused by pigment that the fish deposits around the larval stage of a parasitic digenetic trematode, usually a Neascus spp.

The lifecycle of the "black spot" parasite is complex. The adult parasite is found in a fish eating bird, the kingfisher. The larval parasite is transferred from the infected fish to the bird during the feeding process. In the kingfisher, the larval stage develops into an adult parasite. The adult parasite in the intestine of the bird produces eggs that are eventually deposited in the water. There the eggs mature, hatch, and develop into the miracidium stage of the parasite. The miracidium infects a snail. In the snail, the miracidium develops into the cercaria life stage. The cercaria leaves the snail and actively penetrates a host fish. In the fish, the parasite becomes encysted. In about 22 days, black spots form around the cyst. This entire lifecycle takes at least 112 days to complete.

In general, the presence of the "black spot" parasite does not affect the growth or the longevity of the infected fish; however massive infections in young fish may cause fish mortality. The parasite is incapable of infecting humans and, as is the case with all fish parasites, it is destroyed by thorough cooking. When fish are heavily infected, some anglers prefer to remove the skin to improve the appearance of the cooked fish.


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## firehawkmph (Aug 14, 2008)

Mike,
We used to see the black spots on some fish we caught in Canada, mostly perch. It seemed like it was more predominant in fish that were caught in quiet coves with more stagnant water. If the fish had just a few spots, we would keep it and filet it. If it was all spotted up like somebody sprinkled pepper all over it, we threw it back. Sometime when cleaning, you will find a small white spot that looks like some kind of parasite. We just cut them out. If there was more than a couple in a filet, we threw the filet out. Never had a problem doing it that way.
Mike Hawkins


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## LMRsmallmouth (Jan 10, 2006)

I caught a fish that was extremely healthy and a great fighter but had black splotches, not sure if this is what you are referring to but I had a biologist tell me it was nothing other than stains from sitting in a wintering hole....see below


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## QueticoMike (Sep 25, 2008)

Those are the same type of black splotches I saw on the smallmouth I caught yesterday. I've caught a handful of smallmouth this year out of the river that had this issue. Not sure if I buy the whole wintering hole explaination, I would think it would be caused by some type of parasite. I know a fish biologist in Texas who might know, I'll drop him a line and let you know.


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## [email protected] (Dec 22, 2006)

It is called hyperpigmented melanosis and what causes it is unknown at this time.


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## nixmkt (Mar 4, 2008)

QueticoMike said:


> This is all I could find on the black spots on fish, don't know if this is the same reason the smallmouth have these black spots or not. I've heard some people call it " ich " before, but I believe that is only for salt water fish.....



QueticoMike,

If you are talking about the pinhead size spots, you are correct. I've looked up similar info. myself. Although unsightly, as long as you cook the fish thoroughly, it apparently isn't a problem. If there is an excessive amount in a fillet though, I'll cut some out or not eat that one. Some literature does indicate that it can weaken the fish.



nixmkt said:


> The second factor is Black Spot Disease (Digenetic trematodes). There is info. about this on-line for those interested in the details. In brief, these parasites infest fish skin and meat, and the fish encapsulate them with tissue, resulting in pinhead-sized black spots. These do not affect people when eaten as long as the fish is cooked. Years ago, I would notice a few black spots in fillets. Now many/most bluegills, perch, & crappies I do catch there are "peppered" with black spots throughout. There is no known direct control for these parasites. Some of the literature indicates that these parasites do little harm to the fish. But other literature indicates that they do cause harm. According to the literature, until the parasites are encapsulated by the host fish, the fish loses fats and their oxygen requirement increases. Heavily infected bluegill often enter the winter months in a low fat state with few energy reserves to last over winter, which affects their ability to survive.


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## firehawkmph (Aug 14, 2008)

I have never seen one spotted like the LMR picture above. Looks like he was swimming through a tar puddle. The ones I have seen looked like pepper sized spots.
Mike Hawkins


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## foofoo (May 9, 2005)

Here's a link with some more info (scroll down on the page), basically the same as what nixmkt said:

http://www.fish.state.pa.us/images/pages/qa/fish/worms.htm

I see the same black spotting on about half of the pike I catch in Canada every year, and that's in a very clean and healthy lake. Doesn't seem to bother the fish at all  


As for the tar-like spots on that smallie, I have no idea. Doesn't look like the usual darkening that you see from nest tending.


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## QueticoMike (Sep 25, 2008)

I'm asking about the black splotches that LMRsmallmouth showed in his picture. I'm waiting to hear back from a fish biologist in Texas to see if he has any idea. I think [email protected] is on the right track with hyperpigmented melanosis. I'll let you know what my buddy says about it. I've just always wondered what caused this, maybe Pond is right, nobody knows for sure. It sure makes a pretty fish look ugly.


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## [email protected] (Dec 22, 2006)

It's not black spot. I think the University of Tennessee is researching the what causes hyperpigmented melanosis. The fish in the picture at the beginning of the thread really isn't bad. 

Look at this one.


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## BigSmallieMike (Oct 20, 2005)

I've caught very nice fish with this same affliction in the Stillwater too - I've heard that this can be a very vicious cycle. I seem to recall the discussion saying that the cycle is perpetuated through the sunfish as they eat the snails that carry the larva. At any rate, I'm concerned about the "fish mortality" comment as these are stream fish and I don't think there is as high a sunfish population in the streams as in our ponds/lakes per unit water.


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## QueticoMike (Sep 25, 2008)

Here is the reply sent back from my buddy who is a fish biologist in Texas:

Yes, the pigmentation isn't that unusual but that fish has a lot of it. I'm pretty sure it's genetic, as we've had some hatchery broodfish with considerable pigmentation and it is passed on to the offspring. There's nothing wrong with fish, just it has unusual blotches of black.


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## jimnrg (Aug 6, 2008)

I caught a rock bass that had it bad yesterday which I think might discount the genetics theory. Did you send him a picture of the afflicted fish?


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## QueticoMike (Sep 25, 2008)

Yes, I sent him both pictures from this thread, that is why he said "Yes, the pigmentation isn't that unusual but that fish has a lot of it."


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## [email protected] (Dec 22, 2006)

Here's some more info http://www.tnfish.org/FrequentlyAskedQuestionsFAQ_TWRA/FrequentlyAskedQuestions_TWRA.htm#Melanosis

"It is possible that this condition is genetic, viral, or related to some environmental factor unique to certain bodies of water that stimulates the increased production of melanin. This unusual pigmentation (melanosis) has been observed on bass within most Tennessee reservoirs and in other areas of the country for many years. The Fish Disease Diagnostics Laboratory at Auburn University is currently investigating the cause of hyperpigmented melanosis in Tennessee largemouth bass."


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## Fishman (Apr 5, 2004)

That's the other, more commonly seen "black spot" people refer to. Creek fish get it a lot because of living under stress and confined area during hot parts of the summer.


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## TeamPlaker (Jul 5, 2006)

I had never seen this condition until I read this post.... sure enough, went fishing this afternoon and caught a White Bass on the lower LMR with a black spot on his head.


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## jimnrg (Aug 6, 2008)

Are you sure that's a black spot, Jay? It looks like a yamulka so the fish might be Jewish


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## Wannabitawerm (Apr 13, 2004)

jimnrg said:


> Are you sure that's a black spot, Jay? It looks like a yamulka so the fish might be Jewish


That's funny. 

I've seen the small black pinhead sized spots as well on some of the fish around here, and was told they can also be fresh water mussels in the larval stage.


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## fish4life (Jun 27, 2004)

I've caught quite a few Bass and Crappie in Tenn with spots on them too. None of them appear to have any health issues. It
seems that these may be the equivelant of humans with birth marks which are simply a deposit of pigment in our skin. Just a thought.


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## fish4life (Jun 27, 2004)

They have actually stocked Black nose crappie in Tenn and the offspring have the same black nose on them. The black streak looks alot like the black spots on the fish you were talking about so i think it would be a genetic thing more than any type of desease.


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## TeamPlaker (Jul 5, 2006)

jimnrg said:


> Are you sure that's a black spot, Jay? It looks like a yamulka so the fish might be Jewish


Hahahah.... actually if you look at it in the pic, it looks like the state of Ohio backwards.


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