why my discus has black spots?

[matto]

If they're hiding, maybe dim the lights like I said earlier. Mine stopped hiding when I added floating plants. You got any driftwood or plants to break up the space?

Floating plants are clutch for shy discus. Frogbit or dwarf lettuce would cut the glare. You got a pic of the spots? Might help ID if it's stress or something else.

[virus]

Yeah, pics would help. Also, what's the canister filter media? If it's old or clogged, could be dumping toxins back in. When's the last time you cleaned it proper?