Something weird happened to my acan yesterday. i have a 120g tank with a 50g sump and I have quite a few acans in my tank and everyone is doing great except for this one acan and i have never had any problems with any of them till today. This tank has been online for about 2 months and all the acans have been with me since the very start. When i turned on the light this morning, a head disappeared in the said acan like it was eaten coz the skeleton is still there. the missing head is in the middle part of the rock which makes it weirder because its like that particular head was attacked.
I feed all my LPS tiny chopped shrimp about 2 times a week and there have been no problems with that as well since they are all growing and i can even see tiny heads springing up at the sides of the rock.
I checked my water parameters and everything is fine so im sure its not an issue with the water.
My most immediate suspect would be one of my livestock eating it. I have
1 purple tang
1 mystery wrassse
2 ocellaris clowns
1 royal gramma
1 bangaii cardinal
1 mandarin fish
3 cleaner shrimp
i read up on all of them before i added them and they are all supposed to be reef safe. do you think one of them may be munching on the acan? or could it be a hitch hiking crab?