i have some cured live rock according to the salesman who sold it to me. i noticed some little mushroom like things on one piece and some pink stuff growing on another. So pretty much on each pice there are a multitude of colors. Is this coral growing or just algea? will live rock form corals or wil i have to buy coral to put on the live rock?
The pink is more likely what’s called coralline algae. This comes in pink, purple, red, and pale green and grows on the surface of the rock like a crust (see photo of purple corallin algae on rock: http://www.simplifiedreefkeeping.com/mello/dd/2hardcoral.jpg)
The mushroom like things could be a coral relative if they’re flat and open (http://www.reefland.com/forum/attachments/reef-aquariums/5930-mushroom-pics-18861000_0021__small_.jpg?d=1127490542 , http://www.tylermerrick.com/images/corals/red_mushroom_hammer_small.jpg, http://www.fishtanksandponds.info/images/raw-images/marine/Mushroom%20coral.JPG), but if they have a shape like a puffball and are green or red, it’s more likelely a bubble algae (http://www.reefsanctuary.com/photopost/data/519/medium/61monsterbubblealgae.JPG, http://www.cs.cmu.edu/People/cap/pictures/myreef/main1.jpg ). These can be attractive if there are just a few, but they can overtake your tank if you let them grow. You can remove them by gently scraping them off the surface of the rock, but if you break them, they’ll reproduce. That’s why I suggest taking them out of the tank in a ziplock bag or other container and do the removal there – less chance for a mishap.
You might get real corals, but you’ll most likely need to buy the kinds you want. Depending on the size of your tank, you may want to buy "frags" – pieces that have been broken off other corals for reproduction. These are smaller and less expensive, but will grow to fill the tank.
Here’s a website where you might try identifying some of the things you find: http://www.reefs.org/hhfaq/