Introduction to the different types of corals

[Crease123]

For reef tank owners, adding corals to your tank is one of the most exciting experience. Corals, with their stunning myriad of colors and depth, often introduce a whole new level of aesthetic to your tank.



However, with the many different types of corals available, it can be quite the daunting task to figure out which corals are suitable for your tank. Some corals are easy-to-keep and are suitable even for beginners, while other corals may require specialized attention and should be limited to the more advanced aquarists. Individual characteristics of corals such as its disposition, lighting and water movements needs will all play a part in determining which part of the tank they should be placed.

There is no hard limit to how many corals you can keep in your tank. However, some corals can be very territorial and will attack their neighbors with stinging tentacles. Avoid placing corals too close to each other to allow room for them to grow, as well as to avoid corals attacking each other.

All corals are made of calcium carbonate, and can be broadly categorized into two groups: Hard corals and Soft corals. These two broad categories are further sub-divided into more specific types, which will be elaborated in the paragraphs below.

Hard corals develop an internal skeleton that grows as the corals mature. They stay in one place and do not move around, and tend to have a slower growth rate. They are usually not as colorful as soft corals, but can grow into towering majestic structures. Two different types of hard corals are the Large Polyp Stony Corals (LPS) and the Small Polyp Stony Corals (SPS).

Soft corals, on the other hand, lack an exoskeleton. In addition to calcium carbonate, these corals contain protein as well, rendering them less rigid, giving them the appearance that they are swaying or pulsating in the tank with the water movement. Some soft corals are capable of movement, and will travel to different parts of the tank to find a spot that they like best before settling down. Sub-groups within soft corals are the mushrooms and polyps.

In general, soft corals are considered easier to keep than hard corals. SPS corals are known as the most difficult to keep, as they require very strong lights and regular dosing of key elements in the tank. Soft corals, on the other hand, are generally not very light-demanding, and tend to be more beginner-friendly.

Large Polyp Stony Corals (LPS)

LPS corals get its names from the voluminous tissues of large, fleshy polyps growing on top of smaller skeletons. LPS corals are very popular with marine hobbyists, as they are generally rather hardy and can grow quite fast.



Adequate levels of calcium in the water is needed for these corals to ensure healthy growth. A calcium level of 400 – 450ppm is considered as ideal for LPS corals. Lighting requirements is generally medium – high. LPS corals derive much of their nutrition from the photosynthesizes through the production of zooxanthellae, and supplemental feeding is seldom necessary.

Planning for the placement of LPS corals are important. Many LPS corals have long sweeping tentacles that will extend at night and sting neighboring corals, and thus require plenty of room to avoid aggressive encounters.

Examples of LPS: Brain, Frogspawn, Hammer, Candy Cane, Blastomussa (Blastos), and Acanthastrea (Acans)

Small Polyp Stony Corals (SPS)

SPS corals are notable by their dense and heavy skeletons. They have tiny polyps, much smaller polyps than the LPS corals, that form a “skin” on the coral. In the wild, SPS corals are forms the base of every reef, and provides a habitat for many species.



SPS corals are generally considered to be more demanding in terms of their needs, and hence more difficult to keep. They require bright lights and strong currents. They also need stable temperatures, excellent water quality and a constant supply of calcium to thrive.
Green plate coral

Unlike the LPS, SPS corals hold less zooxanthellae to generate food through photosynthesis. Because of this, there is a debate on whether SPS corals require supplemental feeding. While most seem to agree that additional feeding may not be necessary, it may nonetheless be beneficial to supplement feeding the SPS corals with phytoplankton or coral food such as Coral Frenzy.

Examples of SPS: Acropora, Birdnest, Montipora

Mushrooms

Mushrooms are a soft coral, and are widely considered as one of the easiest corals to keep. They are very hardy, and can tolerate a wider range of water parameters. Due to symbiotic zooxanthellae in their tissues, they can come with a striking range of colors (such as green, blue, purple, red, brown) and patterns (some have solid colors, some have stripes radiating out from the center, while others can be spotted or mottled).



Mushrooms dislike high intensity lights, and may be more suitable near the bottom of the tank if you have strong lights. They tend to prefer low-to-moderate flow of water. These corals are able to move around and settle in parts of your aquarium where they deem the conditions most favorable.

Mushroom corals are generally inexpensive, and can reproduce quickly in a stable environment, making them the ideal coral for beginners.

Polyps

Polyps corals like Zoanthids (Zoos or Zoas, for short) are generally a very undemanding coral, and are great for the novice reef aquarists. They are very hardy, and can flourish under most aquarium conditions.



Zoas often grow like a mat over large areas across a hard substrate, covering bald spots in the tank. They are the corals that come in the widest spectrum of colors, ranging from deep brown to blood red to nuclear green to electric blue. Zoas will prove to be an extremely desirable and colorful addition to your tank.

Zoas’ intense coloration is a product of zooxanthellae living within their tissue, which also help them generate food through photosynthesis. These corals grow best in moderate lighting, with light-to-moderate flow to help them absorb essential trace elements and food from the water.

Zoanthids are considered an invasive species and can spread and grow onto other corals or even equipment. Attention needs to be paid when deciding where to place Zoas so that they do not cover up any corals you have in your tank.

Other Soft Corals

In addition to mushrooms and Zoanthids, there are hundreds of other different types of soft corals. As unique as each of these corals are, their care requirements can vary drastically depending on the species. To facilitate discussion, we will split soft corals into two categories: photosynthetic and non-photosynthetic.

The photosynthetic soft corals, not unlike the Zoas, employ zooxanthellae for photosynthesis. In addition, they also filter the water for additional food and nutrients, and thus require a higher water flow to do well. Corals in this group include Leather corals and Pipe Organ.



The non-photosynthetic soft corals, as you would expect, do not rely on photosynthesis to generate food. As such, they need to be placed in areas of the tank where there is high water flow so that they have a constant supply of food and nutrients. Still, many of these corals require supplemental feeding in order to survive. Because of this, they are generally considered to be more challenging to keep, and should be limited to more experienced aquarists. Corals in this group include Sun Coral, Gorgonians, Dendronephthya, and Kenyan Trees.



http://www.reeftology.com/types-of-corals/'>http://www.reeftology.com/types-of-corals/

[lil0618]

Nice Post!

Really helpful.

[opaquelace]

Could be a sticky thread. Very nice

[SantaMonica]

All LFS should offer a pre-printed pamphlet like this to give to everyone who comes in.