black spots on my silver dollar

My silver dollar (he's about 6") Kenneth has some weird little black patches appearing around his body. They mainly seem to be focusing on the top and bottom edge of him and especially round the face. It almost looks as though dirt has gathered around some scales. It doesnt stick out, but like I say lies on him like dirt.
When all is said and done, he is a very old fish (i got him when he was at least 2 years old about 3 years ago and someone had been bad using him) but he is very active and I love him to bits! Im really worried about what this could be.
It started on a scab he had got from rubbing against a stone while he was unconscious (he's slightly dim and swims into side of tank at full speed sometimes), but anyway.... he has a scab on his side which seemed to get the black bits 1st, about 5 days ago. I assumed it was blood. However it seems to have grown bigger and the wee black patches have moved all over his body. Ive taken pics of him into my usual guy in the fish shop but even he stumped and I cant find anything on the net. I put some pics on a site, which I hoped Ive linked right below. Please please please post anything even slightly helpful - im desperate!

PS - he in a 4' x 1' x 1.5' tank with an oscar, gourami, plecs at 27 degrees


Go to album called kenneth at this link

i have a silver molly.. he was pure silver when i bought him and just recently got some black spots. he had a few at first, then now he has lots. i heard it was just a mix breed... black molly for one parent and white molly for other. or he's part dalmatian. but i have no idea how old he is.. he's not very big. i'll see if i can scrounge a pic. i dont know about your other one? maybe a disease? or maybe nothing to be worried about.. wish i could help more.

he has way more dots on him to this day :

it could be black spot disease. here is a link for some info. HTH

Thank you SO much for such a fast reply! Im hoping angel eyes is right and it just a weird change of colour, cus that happened to an old goldsifh of mine and he was fine. But TSTENBACK I will get the parasite control from the advize of that link - better safe then sorry, anyone know if its easy to remedy?

if it is black spot it is usually quite easy to eliminate. Dont use the med unless you have to. Good Luck and hope everyhting works out.