Whots coming out my elegance

[johnj]

Iv put a elegance coral in my tank today and opened up after 2-3 hours and looked ok but little duller from when 1st saw in shop 5 days ago,. But when lights went out I noticed these long dark black strands , is this poop or something else? I did dip in coral Rx for 5 minutes before putting in tank if that would have done this?

 

[DSC reef]

Could be expelling waste or zooxanthellae. Not sure if the dip would've caused it. Coralrx can be harsh.