black spots on a roach, is it a parasite?

flanum

i caught a good few roach in the river annalee on saturday, one of them was speckled all over with black spots, even in his fins. they werent lumpy or anything, just spots. also noticed this particular roach wasnt slimey at all, in fact felt fairly coarse and had a few scales similar to a carp. but it definitely was a roach, i took a few pics on my fone, ill try to upload them. has anybody heard of this form of parasite/disease/rarity?

Kess73

Rudd and perch also get that. It is called black spot disease, wild fish and aquarium fish can get it. It is caused by parasite worms.

coolwings

It does not seem to do the fish any lasting harm.

Kess73

I am not 100% sure on whether it does harm or not in the long run. I know that when I lived in Germany there was a policy on many waterways for fish caught with it to be destroyed and not to be put back into the water.

I don't think there is anything like that policy in place over here. I have not seen it on an Irish fish in the last ten years or so though,but obviously it is here as the OP has seen it.

ButcherOfNog

That's blackspot disease. It's a type of tape worm. The spots are actually the worms between the scales and the layer of skin (which the mucus protects) covering the scales. Roach and Rudd both get this and seem not to be affected by even large scale infections.

The life cycle of these worms is that the fish get eaten by birds, the worm then matures in the bird and lays its eggs, which get dropped in the birds faeces, which hatch, burrow their way into snails, mature into a larger larval form, which then finds and burrows into fish ..... and round and round we go. Birds help spread the disease to nearby waters.