Plate Coral (Fungia / Cycloseris)

Taxonomy & Identity

Plate corals, also known as Disc Corals or Mushroom Corals (not to be confused with Corallimorphs), are unique free-living corals that don't attach to substrate. These solitary polyps consist of a single large mouth surrounded by radiating septa, capable of impressive expansion. They make excellent sand bed inhabitants with moderate care requirements.

Natural Habitat & Distribution

Fungiids are found throughout the Indo-Pacific, inhabiting sandy areas, lagoons, and reef bases. They're free-living as adults, resting unattached on sandy or rubble substrates. Some species can actually move slowly across the substrate and even right themselves if overturned.

Morphology & Growth Forms

Plate corals are typically circular to oval with a central mouth and radiating septa (ridges) covered in small tentacles. When expanded, tissue can extend well beyond the skeleton, creating an impressive, flower-like appearance. Colors include green, pink, purple, red, orange, and various combinations. Some have contrasting mouth colors.

Lighting Requirements & Spectrum

• Intensity: Low to moderate
• Target PAR: 50–150

Plate corals prefer moderate lighting and can bleach under intense illumination. Their natural sand bed habitat receives less light than upper reef zones. Position on the sand bed or lower rock where light levels are reduced. Blue spectrum lighting enhances fluorescence in colorful specimens.

Flow Requirements & Patterns

• Intensity: Low to moderate
• Type: Gentle, indirect

Gentle flow is preferred for Plate corals. Strong currents can blow them across the sand bed (they're not attached) and prevent tissue expansion. Position in protected areas with just enough flow to prevent detritus accumulation. They can move themselves short distances if flow is problematic.

Nutrient Dynamics & Water Chemistry

Plate corals are moderately tolerant but benefit from stable water conditions. Moderate nutrient levels are preferred. They're more sensitive to water quality than some beginner corals but not as demanding as many SPS species.

Feeding Biology & Symbiosis

Plate corals contain zooxanthellae but are also capable predators. Their large mouth and extended tentacles can capture and consume surprisingly large food items. They are among the most dramatic feeders in the reef aquarium.

• Mysis and brine shrimp
• Chopped silversides or krill
• Larger meaty foods (they can eat big!)
• LPS pellets

Regular feeding 2–3 times per week enhances health and coloration. Watching a Plate coral consume food is entertaining—they can engulf items nearly as large as themselves.

Common Diseases, Pests & Predators

• Brown Jelly Disease (if stressed or damaged)
• Tissue damage from rough substrate
• May be picked at by certain fish
• Can be stung by aggressive neighbors

Plate corals need smooth sand substrate—rough rocks can damage their tissue when they move or settle. Keep them away from aggressive corals. Healthy, well-fed specimens are generally trouble-free.

Compatibility & Placement

Plate corals have potent stinging capability and can extend sweeper tentacles at night. Their free-living nature means they may move to different locations. They should not be placed on or near other corals as they can cause significant damage.

• Best zone: Sand bed only (not rock)
• Give space: 4+ inches from other corals
• Substrate: Fine sand, not crusite or rubble
• Note: May move on their own

Fragging Techniques

Plate corals don't frag in the traditional sense as they're solitary organisms. However, some hobbyists have successfully cut specimens in half, with both pieces eventually regenerating. This is risky and not commonly practiced. Most prefer to purchase new specimens rather than frag existing ones.

Aquacultured Strains & Trade Names

Varieties include "Rainbow Plate," "Ultra Red Fungia," "Green Cycloseris," and various multi-colored specimens. Different species have different shapes—some are circular, others elongated or having tentacular lobes. Many specimens are wild-collected though aquacultured options are increasing.

Difficulty Rating & Summary

Difficulty: Beginner to Intermediate

Plate corals are unique and engaging additions to reef aquariums. Their dramatic feeding response, impressive expansion, and ability to move make them interesting subjects. Proper sand bed placement and regular feeding lead to success. They're ideal for hobbyists wanting something different for their substrate area.