Hello,
Sorry kinda had issues with my (not so smart phone). In terms with my clam I have not a single clue what went wrong. The clam was or has been in my tank for close 1.5 years. Just a few days prior he was out and happy but I noticed a huge difference when I changed my flow. It made him very angry so I moved things back.
Once it was back in place, he came back out into the sun. Then I moved my huge leather (just him on his own rock) which gave the clam more light. Within two days the entire Shell was empty, but he was back to normal right before I made the change. I’m curious if I stressed him out by moving some rocks around. I guess this is a great lesson on why I should leave my hands out of the tank. I feel horrible he was the kinda the center of my tank and looks bare with out him. I will get another one, but as far as predation goes hmmm maybe crabs, I don’t know honestly. My fish I never see eating or picking corals. Pretty sure I don’t have pyramid snails and since they generally feed on them hopefully they all die. As far as food wise nutrients should not have mattered because he was close to five inches. He was more photosynthesis than nutrients. My water parameters are spot on and even sps are doing better. Not knowing will bug me for a long time. He didn’t even have the Shell open and always reacted to movement. Hmmmm