Cleaning live rock

[aquan00b]

I've got a 20 gallon marine tank. I have the following in the tank.

2 Clownfish
1 Cleaner Wrasse
1 Fire Goby
1 Electric Blue Damsel
1 Elegance Coral

I've recently removed the following fish:
1 Yellow Tang
1 Coral Banded Shrimp

I have live rock in the aquarium. One flat piece of live rock has now turned black - it looks quite dirty. I can't clean it by shaking it in the water. Is it okay to clean it with a brush? I don't know how to clean live rock.

[reefnetworth]

you dont clean it. allow the bacteria to grow on it. is it black? or just dark brown? you have alot of fish in a tank that small. have you checked your parameters lately? when was the tank set-up?

[aquan00b]

The setup is 5 months old. Recently the nitrates have been high - around 100ppm - but I've been doing regular water changes and with the removal of the Tang I think it will go down.

The picture shows the colour of the round shaped live rock.

http://www.adeelkhan.net/files/IMG_2625.JPG

[Tankenvy]

I would wait to see if any beneficial coralline algea grows. If it doesn't clear up and turn pinkish or reddish, I don't see any problem with giving it a decent scrub with a toothbrush.

[reefarmer]

that cleaner wrasse will slowly starve to death he needs a large population of fish to live.

[aquan00b]

Oh no! I've noticed a change in the cleaner wrasse since I removed the Tang. Is there anything I can feed it to compensate for the lack of fish?