My RTG got some problem, need advise

[VinLwj]

Recently my RTG has some small black dot on the scale...
What should i do to cure this such things?

This was the first black dot, and now got some yellowish beside the dot...

But the fish overall stil ok, stil active and good appetite.
Please advise, thanks.

 

[ilubtaimei]

look like chemical deposit.....check the food.....this happens often...as long as there is nothing wierd about your aro just leave it alone....

 

[b-man]

doesn't look like nothing serious, i would just keep an eye on it. in the meantime just keep good water conditions and it should clear away