justin1977justi
New member
I am not new but have been out of the hobby for several years. I am setting up a new tank and found these in a hydrometer that was on the glass to keep an eye on salinity flucuations. The only thing in the tank right now is some of my old live rock that i had in the sump of my mother in laws tank. Any idea what these are? The tail portion moves back and forth.