what is this

[Navarchus]

That’s way I never use live rocks!
I never know what you are putting in to your system.
I have a good friend with 900 g system that had a Bermuda triangle in his tank. Fish where disappearing with no reason!
Well one night he was moon lighting the tank to see the coral eating and them he sees a monster crab wandering around the tanks!

I prefer to use dry rocks that I properly cured and run a full, by the book, nitrogen cycle! (In the process I am using some bacteria supplements such as seachem stability, aqua-medic bio-bactor or microbe lift special blend )