After I initially set the live rock in place this 'black' area was larger in shape. Since my tank is now semi-established and the cycle has completed, it seems as if its growing small (and obviously separating).
Any ideas?
Thanks!
probably a sponge, cant really tell. sponges need very specific things to live off of so ur tank cycling is probably killing it. it may stop, grow back or disappear but youll get more just popping up around the tank you never knew were there.
