Black Spot

[Behemoth]

one of my platies has this black square on it's side it looks like it's attached to him, and it has this shiny silvery spec on it to. i am guessing it's some kind of parasite any help would be appreciated. it has been like this for about 2-3 months but the fish never showed any signs of illness. only a few other platies have a shiny spec on them, and it's very shiny.

30 gallon tank
8 ballon mollies
6 painted platies
lyretail molly
upside down catfish
algea eater
random catfish


amonia-0
nitrate-0 according to the lfs
nitrite- 0
ph 7.0

all the levels are fine just wondering if anyone has any idea as to what it can be.

 

[WILDER]

Black patches can mean ammonia burns, bacteria infections parasites, any signs of laboured breathing and flicking and rubbing, has the fish gone thin through not eating and how thin is the fish like a wasting away look.
Any black patches on the fins of the fish aswell.

 

[Behemoth]

he is very thin and small compared to the other platies (even some of the year old babies are bigger), but i do see him eat, but i don't know how much he eats. it's tough to tell because all my platies were born with black spots on them, but you can notice this 1 because it's shape and texture, some of the other platies have black spots on their fins and tails but i think thats from their actual coloring. he does seem to be breathing a bit funny?

what's a good medication for bacteria? incase that's what it is
i have parasite meds already at home?

 

[WILDER]

It could be bacterial or parasite, don't like the sound of the one being thin i would issolate him as it could be internal parasites or fish tb.

Look for black patches on the fins and body along with body swelling. This is a bacterial infection called myxobacteriosis.