I noticed that my big (1 1/4") peppermint shrimp that's been in my tank over a year now has shortened antennae. The only change recently was the addition of a mated pair of banded coral shrimp...maybe he got a little too close :eek1: . Here's what he looks like now (the antenna are all only about 1/2" long)...hopefully he'll do okay until he molts and they might be back...