I've noticed mounds of sand forming in my nano tank. Hitchhikers' Cove was started with live rock so I have all sorts of mystery critters. This mound gets larger every day and is NOT where the current would pile up sand. When I clean the tank )and knock it down) I find it popping up again, sometimes in a new spot. Now it's up against the glass and there's a tunnel which may or may not be related. All ideas are welcome.
American quarter for scale.
American quarter for scale.