Hi what lighting do you have as they require high output lighting such as metal hailides ,, if this
anemone starts to dull in colour then it is not healthy what colour is it

if white they start to go clear if it does this then
QT and see if you can nurse back to health if these die they release toxins in to your tank ,,, They also require
iodine for growth , keep well away from other corals as it will sting and kill them , not good for clowns to host in pretty much only clarki clowns will , red leg hermits will feast on them killing them ,,
Hope this helps