what is this


New Member
20160826_140011.jpg Hi guys.
I am very new to posting, but I have been reading the forums for a few months now.
I have a 29Gal bow tank about 4 !/2 months. It has 20 lbs of live sand, 20 lbs or so of LR a 1 LTA, Bicolor blenny, Fu Man Chu Dwarf Lion, lawnmower goby, Purple Dottyback couple of Feather dusters, snails, and hermit crabs. My water recently tested excellent in all categories. I recently purchased a few hermit crabs and a couple larger shells for them to grow into. I haven't added any rock in weeks. With that said here is my problem. I saw this whitish/yellow thing the size of a minnow darting around the tank with no purpose. Here is a pic, Please help me figure out this creature that has entered my aquatic world. TY