Gary Majchrzak
Team RC
you have a 'closed' 75 gallon system.I know its a small tank for everything I have and I will be ugrading to a 200g soon, but I also have a condy nem and a long tentacle. They have all found their spots and are very far away from each other.
Imagine sitting 48" away from an unfriendly person in the same water for weeks on end.
Different anemone species do not "like" each other.
My first suggestion is to immediately get rid of the Condylactis anemone.
Ensure that you have proper filtration in that aquarium: a protein skimmer and (if at all possible) mechanical filtration in the form of a "filter sock"
100 micron sock minimum.
Is this aquarium running an undergravel filter plate?