Beginner Corals

A blue/purple Mushroom coral

A cream-colored Kenya Tree Coral (small)

Beginning reef keeping is very exciting. The best thing you can do is be patient. Do not put in corals when you do not know your water parameters. Many LFS will offer free water testing and can guide you in corals you can keep. Your water should have very low nitrates, under at least 25. Your calcium should be in a good range as well as your pH and kH. Salinity should be around 1.021-1.025. The tank should be cycled and if your thinking about getting corals, try to wait a few months for your tank to stabilize if it is new. Make sure you have reef-compatible fish. If you have an angelfish or butterflyfish, beware that they might try to eat your expensive corals! If you keep them well fed with high quality food, they should leave them alone. No fish is completely reef-safe; even clownfish have been seen eating corals. Lighting is also a very important aspect in reef keeping and will be explored in depth later.
Here are a couple of great beginner corals that are pretty much bullet proof in their care and usually cheap.
1. Mushroom corals - these corals come in a variety of colors. They don't require much light, water flow, or feeding and grow quickly. Make sure not to get a mushroom with "pipae" or small bumps on the surface; these ones can be harder to keep. These can be placed on the sandbed or close to the bottom.

2. Kenya Trees - These soft corals come in a small variety of colors but definitely add height to your reef. They require medium light and low to medium waterflow. Their branches extend out and sway in the current. You should feed these corals some type of coral food such as oyster feast from Reef Nutrition.

Green Star Polyp Colony

3. Green Star Polyps -These beautiful corals can grow like wildfire when conditions are right in your aquarium. They consist of a purple rubbery base with green "stars" coming out of the polyps. They can stay closed for a while when put in a new tank but just give it some time and they should open up. They will also close at night. These should be fed a coral food as well and be under medium to high light with medium to high waterflow.

Green Button Polyps

4. Zooanthids/Button Polyps - A variety of colors and sizes can probably be found at your LFS. These need medium water flow with medium light. They will close up when you target feeding them, which is normal since they are trying to "catch" the food.
When you get the corals home, acclimate them like you would a fish and make sure to increase your rate halfway through, this helps keep the temperature stable in the bag/bucket.  Once you put the corals in the tank, try to start your corals on the bottom of your reef and then move them up if they need more light.