What happened to my clam? I blame an urchin.

I had a crocea clam doing great in my tank - it looked colorful and amazing. It was happy and open every day and quick to react to movement. I don't have a doubt it was in great health.

 

Sorry the above went through before I was finished!

Tankmates are a pair of clownfish, a firefish (I've since given to a friend), a tailspot blenny, a watchman/shrimp pair and a zebra catalina goby. Cleanup crew consists of sexy shrimp, peppermint and fire shrimp, and some little hermits and snails.

I have the Coral Compulsion LED fixture hanging above.

The clam quickly attached to a rock lower in the tank, but out of the reach of the pistol shrimp. There was no fading or stressed look about it. If something scared it, it was quick to open again. No one was picking at it that I ever noticed in the weeks I had him.

Then I added an urchin, I think a pencil urchin. I did my research and was prepared to remove it if it started bothering my corals, but I never read they were a threat to clams! The next morning after adding the urchin something had ripped my clam off the rock it was attached to. It was ripped up really bad - the whole gland remaining stuck to the rock. My poor clam didn't survive and it was heartbreaking.

Something that was moving around in the middle of the night tore my clam off the rock, and I believe it was the urchin, but I can't find any info to back this up. I have since moved the urchin into another tank.

I would love to get another crocea clam someday when I find another nice one, but I can't stand to think this could happen again.

Any thoughts? Do I have another threat?

 

The pencil urchin is about an inch in body size, but the spines make it about twice that in diameter. The clam was a little larger than the total size of the urchin, but not by much at all.

I knew the urchin might bother the corals, so I was going to move him out if he did, but I figured I had a lot of coraline and other algaes it may prefer to eat instead. This was the last thing I expected, and I've been pretty upset about it. My clam was starting to show some nice new shell growth. I would never want this to happen to another one, but I don't want to see another clam killed. My pistol shrimp is the only other possibility I could think of, but he stays on the ground... Plus, the pistol shrimp barricades himself and the goby in at night, and this incident happened overnight.

BTW Pete, thanks for the blue clove polyps I picked up at frag fest. They're looking great!

Anyone clam-free want a nice purple urchin? /DesktopModules/ActiveForums/themes/_default//emoticons/smile.gif Seriously - I don't think my frogfish needs a roommate.

 

Mmm I don't think that's possible. I did read about them when I was getting a clam, so I inspected it to make sure it was free of pests. If it had just been eaten, I might still suspect that, but I don't think those snails would be capable of ripping my clam off his rock and tearing off the whole byssal gland.

At this point the only other thing that could be that strong is my pistol shrimp, but since this happened overnight when my shrimp and goby were barricaded in their den, he has a pretty good alibi. I also had the clam where the pistol shrimp doesn't really go. It was not on the floor of the tank.