SPS bleach from base up

[YVR]

Sounds like RTN. It can happen really suddenly on a seemingly healthy coral that has been in a tank for years. I've lost a few corals the same way too. I keep an eye out for any signs of RTN and immediately cut off the receding/ dead parts and dip the entire coral in an iodine bath like TM Pro Coral Cure. I prefer to be proactive when I see tissue recession now.

 

[YVR]

RTN can happen really suddenly on a seemingly healthy coral that has been in a tank for years. I've lost a few corals the same way too. I keep an eye out for any signs of RTN and immediately cut off the receding/ dead parts and dip the entire coral in an iodine bath like TM Pro Coral Cure. I prefer to be proactive when I see tissue recession now.

 

[Eckolancer]

AEFW take coral out dip and dip again and again and again. Have seen it many times in past before I started reading up on AEFW.