I had a Peppermint Shrimp several months ago. I only got one cuz I wanted to try it out and see how it did in my tank that at the time was only a few months old. I remember that it hid for about 5 or 6 days straight inside all the rockwork. After about a week it started coming out, and I was soon feeding it pieces of krill by hand. A few weeks later I added my last fish, a Valentini Puffah....and it coincided with the Shrimp for a week or 2, I actually saw it "pull up" for a clean-up a few times. But one day, I just happened to look over the tank, and at that very moment....all hell broke loose. I saw the shrimp swimming towards the top...legs and antennae eaten off, and the Puffer taking nips of it, and I even saw my Diamond Goby jump up and take a bite at it. Then my Tank Raised Maroon Clown even sped over for a bite! I thought it was ok, cuz nothing had happened for a few weeks, but the Peppermint Shrimp was soon dead and I scooped it out. I'm not so sure your specific fish would eat it, I would be willing to bet they are hiding. Give it some time and make sure some food drops to the bottom for 'em, drop feed to the bottom after the lights have been out for an hour or 2.