Related FAQs: Merulinids 1, Merulinids 2, & FAQs on: Merulinid Identification, Merulinid Behavior, Merulinid Compatibility, Merulinid Selection, Merulinid Systems, Merulinid Feeding, Merulinid Disease, Merulinid Reproduction/Propagation, & Stony/True Coral, Coral System Set-Up, Coral System Lighting, Stony Coral Identification, Stony Coral Selection, Coral Placement,  Foods/Feeding/Nutrition, Disease/Health, Propagation, Growing Reef Corals,  Stony Coral Behavior, SPS Identification, SPS Behavior, SPS Compatibility, SPS Selection, SPS Systems, SPS Feeding, SPS Disease, SPS Reproduction, Related Articles: Small Polyp Stony Corals,  Stony or True Corals, Order Scleractinia, Dyed Corals, /The Best Livestock For Your Reef Aquarium:  Corals of the Family Merulinidae, Part 2 Part 1: To Echinopora Part 3: Genus Merulina Part 4: To Genus Paramontastrea Part 5: Genus Pectinia

Bob Fenner

Genus Hydnophora Fischer de Waldheim 1807, Horn, Velvet, Knob Coral. Have short tentacles that originate at base of their hydnophores. More than capable of strongly stinging other sessile invertebrates. Eager feeders on sizeable meaty foodstuffs. Easily reproduced through fragmentation of healthy colonies. /WA Corals: massive, encrusting or branching • highly fused corallite structures (hydnophores) where septa converge to form a pyramid • may be hidden by tentacles

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Hydnophora exesa  (Pallas 1766), Occurs as both encrusting and branching forms. These colonies open during the day (wild ones only at night) in captivity.

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Verticals (Full/Cover Page Sizes Available)

Hydnophora grandis Gardiner 1904. Thicker mostly circular branching, more prominent mounds (hydnae) for bases. This colony in Bunaken/Sulawesi/Indo.

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Hydnophora rigida (Dana 1846). Thin, flattened, pointed branches. The first two images below are a smaller colony on the reef flat and one further down in slower, less lit water in Fiji, and the last a close-up in Bunaken/Sulawesi/Indo.

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