how uch live rock would be good eough for a 120 gallon tank that houses a coral catshark also would corals be a good idea to house with them e.i. mushroom corals
i agree ,with shark tanks[ imo]the rock is only there to provide some thing similar to a natural habitat, somewhere to hide and feel relaxed. filter media and skimming should be the basis of you fitration along with water movementyou dont need any rock if you like, just be shure to have enough bio filtration and your good to go. i have about 100lbs in my 180 though covering a 6" pipe that the sharks hide in, and the rock provides hiding places for all my other fish.