We have the option to keep our saltwater tank a “FO”, or fish-only tank, a “FOWLR”, or Fish Only With Live Rock tank, or a reef tank. We want a reef tank, and because we want the focal point of the tank to be the reef itself, a large part of our tank will be live corals. Choosing corals for your reef aquarium is a lot of fun, but there is lot you need to know.
Why corals? For anyone who has seen a reef tank, watching the swaying corals is mesmerizing, even more so that the other inhabitants in the tank. It is so beautiful, it’s like having a small piece of the ocean right at home.
Because we want corals, we will need to make sure that the fish and invertebrates we choose are compatible to a reef environment. Fish such as the Princess Parrotfish and the Butterfly fish are beautiful, but no matter how much we may want those fish, they eat corals, and are not an ideal addition to a reef tank. Some invertebrates eat coral as well, such as the camel shrimp.
Some aquarists choose not to have corals because of the increased maintenance and equipment needed to keep them healthy. Water quality needs to be pristine, which means keeping an eye on water chemistry constantly and possibly performing water changes more often. Lighting is also very important, and can be the most expensive part of the aquarium. Corals need light to grow, so depending on the type of corals kept, lighting may need to be increased. We have 2 T5 bulbs, one blue and one white, which we are told are sufficient for many corals. Corals are also sensitive to water flow, so having the right flow-rate from your powerheads and positioning them to create the type of flow needed for a specific coral is also important. Water flow brings food to the corals, clears debris from them, and washes away mucus that can form as a result from aggressors.
Corals are actually animals, with plant-like appearances. There are about 5 main categories of corals for a reef tank. They are LPS corals, SPS corals, Mushrooms, Soft Corals, and Polyps. Here are some very basic descriptions of each.
LPS coral, or Large Polyp Stony corals get their name from their large polyps, and their calcareous skeleton. These corals are fairly hardy, but require a calcium level of 400-450ppm to build their skeletons. If this is not adequate in the tank, an aquarists may add this to the tank using a supplement. These corals have a tentacle that comes out at night that sweeps the surrounding areas for other invading corals and can burn them with this tentacle if touched. It is a good idea to wear gloves when handling corals for this reason.
SPS Corals, or Small Polyp Stony corals also produce a calcareous skeleton, and have smaller polyps than LPS corals. They require more specific tank conditions to grow and be maintained such as high intensity lighting and perfect water conditions.
Polyps, also known as Zoanthid corals are very hardy and easy to maintain in reef tanks. They spread like ground cover over rocks and other equipment and come in a variety of colors. They require moderate lighting and low to moderate water flow.
Mushroom corals are probably the easiest corals to maintain in a reef tank. They come in almost every color and size imaginable. They do not produce a calcareous skeleton and prefer low light and low to moderate flow.
Soft corals are placed in two groups, those that use photosynthesis, and those that don’t. The soft corals that use photosynthesis need good lighting as well as high water flow. The soft corals that do not use photosynthesis are not recommended to new aquarists and are quite hard to maintain. They need to be fed daily and require strong flow and placement out of direct light.
We have chosen 4 types of corals for our tank so far. They are the Green Star Polyp, the Hammer Coral, the Neon Trumpet, and the Ricordea Mushroom.
The Green Star Polyp coral is a soft coral that uses photosynthesis for energy. It is distinguished by many bright green polyps connected together on a purple mat. They are open during the day and closed at night or when disturbed. They are considered very hardy corals, require low to moderate light levels and moderate water flow.
The Hammer Coral, also known as the Anchor coral, or the Euphyllia Hammer coral is an LPS coral. It requires moderate lighting and water flow. As with many LPS corals, the Hammer corals have a sweeping tentacle that emerges at night that will sting any nearby corals to deter them from growing near them.
The Neon Trumpet Coral is from the LPS group of corals and requires moderate lighting and water flow. It is highly fluorescent and looks amazing under the aquariums blue lighting.
Lastly, the Ricordea coral is from the mushroom group. It comes in numerous colors, but we chose orange, as the other three corals we chose were green. This coral requires moderate water flow, and moderate to high lighting.
So far, a great start to our reef tank. We will let these corals settle in and fill out a little before purchasing more, if we can wait that long.