It is important to have live rock in your tank. Be careful where you buy it though, especially local petstores tend to have unhealthy live rock.

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I have both live rock and live sand in my 125 gallon reef setup. The corals and anenomes need the structure that the rock provides. I always enjoy the reef-scaping that you get to do when you add a new piece. Since it took so much live rock for a 125 gallon tank, we ordered the bulk of it from a discount supplier, and then hand-picked the rest of the pieces from a local supplier.

Pros: great base for marine tanks

Cons: none

I started my reef tank with live rock and live gravel. I love to use it because in addition to the rock, you often get other marine life such as tube worms, baby snails and sometimes even an urchin or two. It really helps to get a tank started because of the live cultures already on the rock.

Pros: NA

Cons: NA

I have accumulated a lot of LR over the years for my sw tank. It looks great when it has lots of colors on it. It is a great source of filtration and gives the fish lots of hiding places.

Pros: looks awesome, good filtration and hiding spots for fish

Cons: expensive!

A must have for a salt-water tank. I've been using a live rock for over a year now.

Pros: Good for the fish

Cons: None