The Best Coral for a 20 Gallon Aquarium

Corals make colorful and exotic additions to a saltwater aquarium. Coral has a reputation for being a finicky animal that does not survive well in captivity. However, there are many species of coral readily available that thrive in home aquariums. Whether searching for a large specimen for a centerpiece or several small species to accent your marine landscape, you can find several varieties of coral that are well-suited for a 20-gallon aquarium.

  1. Mushroom Coral

    • Mushroom coral is the common name for soft corals in the genus Actinodiscus. Mushroom corals are extremely hardy, colorful corals that are easy to maintain. There are numerous varieties of mushroom corals available and all have a short base and a round disc-like cap that is sometimes ruffled. Mushroom corals vary in size and color; some specimens have multiple colors and patterns on the mushroom cap. A mushroom coral requires ample space and should not be planted near other corals, since its natural defense includes tentacles extending out of its cap that might damage surrounding corals. In addition to space, mushroom corals need plenty of light and a strong current in the tank in order to thrive.

    Button Polyps

    • Button polyps are a diverse group of invertebrates also known as zoanthids. Zoanthids are a distinct group of marine life that is extremely resilient and closely related to soft corals and anemones. Button polyps usually form colonies on any hard surface in the aquarium. Each individual polyp has fine tentacles that radiate from the edge of the disk on the upper portion of its body. Button polyp coloration is highly variable among the large number of species commonly available; common colors include yellow, green, pink and red. Button polyps are simple to care for, but require high volumes of lighting in order to photosynthesize and grow. Like many colonial marine organisms, button polyps will spread rapidly and may start to crowd out other corals, especially in 20-gallon aquariums. Exercise caution when handling zoanthids, as they contain symbiotic bacteria that produce palytoxin, a toxin that can cause skin irritation on contact.

    Star Polyps

    • Star polyps are small, elongated corals in the genus Clavularia. Also known as starburst, mat or daisy polyps, star polyps are easy to care for and commonly available. They are colonial polyps with several individuals attached to the same piece of live rock. Once established, star polyps can be easily propagated by making small cuttings at the base of the colonial growth. Star polyps require ample light and good water movement, which allows them to sway with the current in your tank.