RTN in Red Lobophyllia

[karburn]

Out of the blue I discovered some tissue necrosis on an established red Lobo in a client's aquarium. A few months ago some hairy mushrooms had crept over and just barely contacted the Lobo, but I moved it laterally - end of problem. Last visit (I go once a week) there was about a 1" coval patch of tissue loss, exposing the skeleton along one edge. This is a specimen about 6" long and 4" wide - a beauty. The tank is stable as can be, but I started checking water parameters anyway. The SG had crept up to about 1.028 and nitrate measured 10, but that's it. (pH 8.13, Ca 500, Sr 6, Mg 1500, Iodine .6.) No new neighbors, no other movement. The tank has 4 110W VHO URI bulbs, 2 white & 2 blue, and this lobo sits about 12" below the surface. Circulation is good - not direct, but good. I did about a 15% water change, easing the SG back down to 1.026. Also put a bag of Kent Reef Carbon in the sump return, just in case there's some toxin. Grasping at straws. I don't want to lose this one. Feeding used to be a once a week dose of Micro-vert, but I recently switched to Marine Snow and I'm going to start DT's Phytoplankton next week. Good results on my own stock.

Any ideas on potential causes of the tissue loss are appreciated - as always.

[Anthony Calfo]

I'm fairly certain you hit the nail onthe head already: the mushrooms. They are very noxious although they don't look it. And it is a common misconception that corals have to touch to burn or kill. Not the case at all... the sensation of a neighbor can stimulate sometimes excessive allelopathic exudations until the water becomes so concentrated (often takes weeks/months) that one or both/other coral die in the toxic soup.

In this cases, you saw a negative response before.

Ozone and extra water changes certainly temper the effects of alleloapthy.

Best regards,

Anthony