Candy Coral: discolorationa nd tissue damage?

[oldbob50]

My Candy coral just started showing a problem two days ago. One side of the foreground polyp is a darker, purple color and appears to have some tissue damage. Two days ago it look like the one behind it. The double polyp behind it may be starting the same thing. It is slightly discolored. What is happening? What corrective actions are recommended. The is a very stable tank. Water parameters tested yesterday: PH 8.1, Ammonia and Nitrites 0, Nitrates 2.5, KH 12.5, Phosphate 0, Ca 440, Mg 1260, Salinity 1.025, Temp 79.3. Only recent changes to the tank have been a new grow light in the fug., new chaeto and the addition of a long tentacle nem three weeks ago.

 

[Crabs McJones]

My Candy coral just started showing a problem two days ago. One side of the foreground polyp is a darker, purple color and appears to have some tissue damage. Two days ago it look like the one behind it. The double polyp behind it may be starting the same thing. It is slightly discolored. What is happening? What corrective actions are recommended. The is a very stable tank. Water parameters tested yesterday: PH 8.1, Ammonia and Nitrites 0, Nitrates 2.5, KH 12.5, Phosphate 0, Ca 440, Mg 1260, Salinity 1.025, Temp 79.3. Only recent changes to the tank have been a new grow light in the fug., new chaeto and the addition of a long tentacle nem three weeks ago.

Where is the LTA in the tank? And did it move around at all? Could be damage from another coral or the nem

 

[oldbob50]

The Candy is by itself and the LTA is a good 16 inches away and is not moving. The closest other coral is a Blue Sympodium frag that is six inches from the Candy. If it is physical damage it would have to have come from a fish or a crab. Fish in the tank are 2 clowns, 2 blue damsels, tailspot blenny, six line wrasse Mandarin dragonette, and a scooter blenny. Crabs are blue leg and red leg hermits. This coral has been in this tank with all of these animals for about two months and has been growing like a weed.