Coral grows in warm seas and are alive. There are lots of different kinds of coral. Here are the types of coral that I observe in the Bahamas: brain coral, mustard hill coral, finger coral, elk horn coral, fan coral, and sea ship coral. Those are the main types I see and here are pictures I took.
Brain Coral
Sea Whip Coral
Finger Coral
Fan Coral
Mustard Hill Coral
Elk Horn Coral
All corals have polyps. Polyps are the living parts of coral. They are tentacle like creatures. They are like builders. They build the coral. Brain coral polyps come out only at night. Brain coral likes facing the surface of the water. Mustard hill coral polyps come out in the daytime. On all kinds of coral polyps, they either come out at night or day. Finger coral have day polyps and comes in many different colors like green, purple, pink and grey. Elk horn coral is the biggest coral. It grows six inches every year. Fan coral lives on drop-offs and finally sea whip. Sea whips come in sea like forests. Here is a picture of polyps.
Logan
Truansea 
Great Blog Logan. We keep trying our stove top cooker. (Omni)
Hi to your mom and dad.
I love reading your posts, Logan! You are learning so much this year.
Tell Cole and your parents hi for me.
~Mrs. Tacke
Hey Logan and cole it looks like your having a great time. We got two Guinea pigs. I was wondering what the name of the blanket was that your mom got for your pigs to help with cage cleaning?
I’m glad you got two guinea pigs. Mom used a towel on the bottom of the cage and put a fleece blanket on top of it, tucking all the edges down and around the towel. Logan
Great post! I grew some coral in a saltwater fish tank once. Of course what you are seeing more beautiful.