Silver dollar fish question

HI I have two silver dollers which iv had since they were about an inch long, There now about 5inches long,
They had fin rot a while back which I treated and the fins grew back,
Now one of them has a large dark round mark on its side near its gill cover and its tail fin has I dark line running from bottom to top
on the end of the fin.
They share a 4foot tank with two cory's, a pleco and two loaches (which I hardly ever see because I think they bury themself in the sand by day)
All the other fish seem fine,
Any idea's
Cheers james
   

 

I think it is black spot heres the link to freshwater diseases and sicknesses black spots in there it says the treatmment and what it looks like and everything

 

Thanks il have a look

 

Just had a look at the site and it says black spot symptoms are small black spots and my doller has large black spots,
Il treat them for black spot and see if it clears up,
Many thanks
james

 

Your welcome other then that I don't know what it could be, but I'm not a fish expert, I bet if you give it a couple days a expert will get back to you. Though I know your fish might not have that time to wait, so I hope that helps

 

I don't think there is anything wrong with your fish. I have silver dollars they have black spots and they are fine. I think its because your fish are healthy and on a good diet!
-Brianna

 

I have 4 silver dollars (about 18 years old!) - occasionally one or more will exhibit spots near the gills - it is just a darkened area, not sharply defined - it goes away after a few days - I think it may be some natural phenomenon related to breeding or something - I always panic when it shows up because it is quite pronounced and at first glance seems like it must be a wound, or parasite, or something. I'd look closely to see if the gills are inflamed; see if it looks like the skin is damaged where the spot is; if not, keep a close eye on it for a day or so and see what happens.