Soft Corals
Soft corals are a group of corals that do not produce the large hard calcium carbonate skeletons commonly associated with SPS and LPS corals. Instead, they rely on flexible tissues and internal structural elements called sclerites for support.
Soft corals are among the most popular corals in reef aquariums due to their hardiness, natural movement, and ability to thrive in a wide range of conditions. Many species display flowing polyps that sway with water movement, creating a dynamic and natural appearance within the aquarium.
While they may not build massive reef structures like many stony corals, soft corals remain an important part of both natural reef ecosystems and home aquariums.
Why Are Soft Corals Important?
Soft corals contribute to the diversity and biological complexity of coral reef environments.
They help support:
- Reef biodiversity
- Habitat creation
- Nutrient cycling
- Natural reef aesthetics
- Ecosystem balance
In aquariums, soft corals are often valued for their movement, coloration, and ability to adapt to a variety of reef conditions.
What Makes Soft Corals Different?
The primary characteristic that separates soft corals from SPS and LPS corals is the absence of a large external calcium carbonate skeleton.
Soft corals typically feature:
- Flexible tissue structures
- Internal support elements called sclerites
- Prominent polyp extension
- Natural movement in water flow
- Reduced skeletal growth demands
Because they are not building large hard skeletons, their nutritional and water chemistry demands often differ from those of stony corals.
Common Types of Soft Corals
Popular soft corals include:
- Zoanthids
- Leather Corals
- Toadstool Corals
- Kenya Tree Corals
- Xenia
- Green Star Polyps
- Clove Polyps
- Colt Corals
Each species has unique growth habits, appearances, and care requirements.
How Do Soft Corals Obtain Nutrition?
Like many reef organisms, soft corals use multiple nutritional pathways.
Photosynthesis
Many soft corals contain zooxanthellae that produce energy through photosynthesis.
Heterotrophic Feeding
Soft corals can also capture and utilize:
- Phytoplankton
- Zooplankton
- Marine snow
- Dissolved organics
- Suspended food particles
- The balance between photosynthesis and feeding varies depending on the species.
Soft Corals and Coral Nutrition
Nutrition helps support:
- Tissue growth
- Polyp development
- Reproduction
- Coloration
- Overall health
Soft corals utilize nutrients such as:
- Proteins
- Amino acids
- Fatty acids
- Vitamins
- Trace elements
Although many soft corals are considered forgiving, they still benefit from a stable and nutritionally balanced environment.
Soft Corals and Water Chemistry
Because soft corals do not build large external skeletons, they generally consume significantly less calcium and alkalinity than SPS and LPS corals.
However, stable water chemistry remains important.
Healthy soft corals still depend on:
- Stable salinity
- Consistent pH
- Appropriate nutrient levels
- Good water quality
The absence of a large skeleton does not eliminate the need for proper reef husbandry.
Common Misconception: Soft Corals Do Not Need Feeding
Many hobbyists assume soft corals survive entirely through photosynthesis.
While some species rely heavily on light, many soft corals can benefit from the nutrients provided by plankton, dissolved organics, and other food sources.
A balanced nutritional environment often contributes to improved growth, coloration, and overall vitality.
Soft Corals and Growth
Many soft corals are known for their rapid growth under favorable conditions.
Growth may be influenced by:
- Lighting
- Nutrition
- Water flow
- Nutrient availability
- Environmental stability
Some species can spread quickly and become dominant within an aquarium if not managed appropriately.
Soft Corals and Reef Aquariums
Soft corals are often recommended for beginners because they tend to be adaptable and forgiving.
Their movement, color, and ease of care make them popular additions to:
- Beginner reef aquariums
- Mixed reefs
- Soft coral displays
- Lagoon-style systems
However, like all corals, they still benefit from proper husbandry and a stable environment.
The Bottom Line
Soft corals are flexible corals that lack the large hard skeletons found in SPS and LPS corals. Through a combination of photosynthesis and feeding, they obtain the energy and nutrients needed to support growth, coloration, and overall health. Their movement, adaptability, and unique appearance make them an important and popular part of many successful reef aquariums.
