I think my peppermint shrimp had a bad molt a few days ago. Normally he comes out of his hiding hole eagerly for twice-a-week mysis shrimp when I feed the coral, but the past week he didn't come out. About two days ago I saw a fresh molt, so I assumed he was just going through a normal molt. However, this morning he was out and upside down on the rock, with slow labored breathing. I noticed one rear leg was just a partial translucent stump, and one of his pincers was also missing. I can't tell if his shell has hardened or not, but his color looks normal.

Was it likely to be a bad molt, and if so is there anything I can do to help him survive or recover? I dumped a few pieces of nori in the tank, in case iodine was low. When I came to check a few hours later, he was resting upright and breathing better, body plopped on a rock instead of standing on his legs. I don't know if he ate the nori, nor whether it could help that quickly. My pom-pom crab seems to have had a healthy molt about 10 days ago.

I'm sure it's not other predators, because at 4" long he's by far the largest thing in my six gallon tank (other much smaller creatures are a small neon goby, a shy pom-pom crab, sexy shrimp). I've been doing weekly 5-10% water changes with RO water and IO Reef Crystals, and just did a 10% change two days earlier. I feed about 15 pieces of mysis to various corals, so I thought there would be decent iodine from the shells. The only thing I've been dosing is about three drops of Coral Amino along with the mysis. My corals have been looking healthy overall with continued growth during this time.

Peppermint's get a bad rap here often, but mine seems to play nice with the corals and other inverts, so I'd hate to see him go.

Ahh, too late, came home from work to find peppy dead sitting near the same spot. Sad as it's the first real casualty in my three months since starting the tank.

Tested water and SG has been 1.024-1.025 the past week, other basic params near zero. Only strange other thing in the past week, which I'm really just realizing now, is that a torch coral and kenya tree are both ailing as well. These two happened to sit across from each other, about an inch apart, and while I never saw them touch in the flow, perhaps they were extending/leaning into each other. The torch is mostly retracted, and a number of the arms have black at the tip, I think the real tips actually fell or melted off. The kenya tree is also retracted now with a number of ends turning into brown goo. Don't know if some chemical warfare was affecting the shrimp.

you can see if your shrimp is breathing?

Well, I guess it's not really breathing , but the breastplate where all the arms attach was heaving at a steady pace. That's how I could see immediately it was still alive this morning, when it was both on its back and later right side up, even though it wasn't moving its legs or antenna. Whereas when I came back in the evening, it had all its color but immediately looked dead as it was dead still - but I had to touch it to make sure.

I can't remember if I noticed this "breathing" movement before, because the rest of it was always in constant motion - legs, pincers, antenna.