Is that a peppermint or camel shrimp in the pic? I asked if you had any before...
Next is how much do you feed your tank?
Right now you are looking for causes.
1)Shrimp eating the flesh could be one of them. Peppermint shrimp love the flesh of acans if they are not "fed." That means they can be "not reef safe."
2)Your light fixture is not made for growing corals. Even if you change the bulb.
3)Flow for your surface is as important as flow on on the coral for gas exchange.
4)Your corals produce O² for your tank during the day and absorbing to much at night. Remember they are animals and do breath. They need flow to help expel gas exchange.
5)Your filtration probably has bioballs in it. Those things are garbage and detritus traps. The surface area to hold beneficial bacteria is the lowest in all the hobby at like 170. Beef it up with marine pure balls that has 2,400, add some Nite-Out ll to your filtration.
6)Do not target feed zoas. They do go into protection mode. Broadcast feed the tank.
Next is how much do you feed your tank?
Right now you are looking for causes.
1)Shrimp eating the flesh could be one of them. Peppermint shrimp love the flesh of acans if they are not "fed." That means they can be "not reef safe."
2)Your light fixture is not made for growing corals. Even if you change the bulb.
3)Flow for your surface is as important as flow on on the coral for gas exchange.
4)Your corals produce O² for your tank during the day and absorbing to much at night. Remember they are animals and do breath. They need flow to help expel gas exchange.
5)Your filtration probably has bioballs in it. Those things are garbage and detritus traps. The surface area to hold beneficial bacteria is the lowest in all the hobby at like 170. Beef it up with marine pure balls that has 2,400, add some Nite-Out ll to your filtration.
6)Do not target feed zoas. They do go into protection mode. Broadcast feed the tank.