Possible hitchiker

[FlyingPotato]

I am currently setting up a 10 gallon nano reef tank. About 2 weeks ago I bought 10 lbs live rock from kp aquatics and added it to the 8 lbs of dry rock I already had. My cycle is nearing the end and the live rock has tons of stuff growing on it. After ammonia was barely noticable I added 3 mollies just to have something in the tank while I waited. One didnt transition from freshwater to saltwater very well but the other two were happy and healthy. Day 2 and a second goes missing. I looked in every place I could to try and find it but it was just gone. I forgot about it and saw no noticable ammonia spike. Yesterday my last Mollie just vanishes also. No trace. When I first got the rock I found a small crab which I moved to a separate tank. Today the crab looked like it had died so I put it in the tank to fuel the cycle until I was ready to add fish. It was wedged in between 2 rocks so the current couldn't move it. Again, it vanished within an hour. Do dead fish get lost in rockwork that easily or could something be eating them? I am adding my cleanup crew friday and dont want them to disappear also.

 

[brmreefer]

There might be some bristleworms hidden within the rocks. There are some animals that get active at night. Maybe consider looking in the tank after a couple hours of "lights out."