What could this be?

[lobonator]

Hey everyone,

Im still pretty new here but I just lost a discus tonight. It was a beautiful wild Cuip from Santarem to make things worse.

Anyways, everything was totally fine 3 hours ago, then came back to one fish swimming erratically around the tank. Soon after it was off kilter and leaning all over. The rest of my discus were all fine, are still fine now. When I took him out he looked like this (see photo). Also all my water params are good. Ammonia =0 Nitrites =0 Nitrates= 10. Any ideas what this could be? IMG-20170727-WA0007.jpg

[Phillydubs]

Wow that's weird. It never showed that black till death. Was it a recent addition? Quarantined ?

Did it hit or swim into anything you know of?

What's your maintenance regiment ? Size of tank? Number of fish?

[Second Hand Pat]

Hi Aidan, the picture was taken after the discus had died? Discus will do this when they are about to die or have passed. Sorry to hear about your loss.
Pat