Who's chomping on the Cleaner Shrimp's antennae?

The suspects:

1 Coral Beauty
1 Yellow Tang
2 Clarkii Clowns
2 Yellow Tail Blue Damsels
4 Green Chromis
6 Red Leg Hermit Crabs

The pair of Cleaner Shrimp were magnificent, proud members of the tank,
claiming a prominent outcropping and hanging there for all to see and
for everyone to visit for cleaning; especially active at feeding time,
swimming and jumping about to catch another morsel...

Then they disappeared. Took to hiding and wouldn't come out. It seemed
very sudden to me - one day they were out and about, and the next they
would barely show themselves even at feeding time.

After a few days of puzzling over this and only catching fleeting
glimpses of a leg or two way back in the rock, I finally saw one emerge
to eat - and his antennae were drastically shorter and uneven!

Who's been munching on the Shrimp's antennae? The other shrimp?? He
doesn't look damaged at all, but he almost *never* comes out anymore,
either... Is he just better at evading the marauder, or is *he* the
culprit?

--Charlie Henderson