Cleaner shrimp problem

ello, I've lost 2 cleaner shrimps in 3 months . I don't understand why!! Here are my water parameters:

PH: 8.3
Nitrite: 0
Nitrate: 20
Amonia: 0
Salt: 1.023
Temperature: 80 F

Got 1 Ocellaris clown and 1 yellow tail damsel in there off and 2 mini bluelegged hermit crabs.

The only thing I would see left checking would be the phosphates, I'm getting a test for that tonight...

I've read that blue legged hermit crabs are known for killing snails. But it could also be the territorial clownfish or the more aggressive damsel.

HTH, BK

are you adding any elements, iodine, iodide, trace, any extra to the tank?

Are you sure they are dying?? the shrimp do molt regularly and their little exoskeletin looks like a little body.

How long has the tank been up and running?? What size tank? How much LR? Your Nitrate is a tad high, how often do you do water changes?? How big are your water changes? What kind of salt??

I have had shrimps and never added any iodine
The yellow tail damsel can be nasty as well. how big were the shrimp ?

most fish might not go after a cleaner shrimp, cause of the white on them, fish see that as a help and not an enemy. unless you had a trigger or a hawk fish which might go after them. what size were the shrimp. maybe died of old age. might be a lack of fish as they are cleaners and they do eat parasites. might want to get a few more fish and get only one cleaner.