Redspotted Clown Goby

Geographical Origin and Habitat: Gobiodon erythrospilus is widely distributed across the Indo-Pacific, from the Red Sea and East Africa to Japan, Australia, and the Tuamotu Islands. It is strictly tied to shallow coral reefs, living exclusively among branching Acropora colonies.

Taxonomy and Morphology: Classified within the Gobiidae family. It features a scale-less, compressed body coated in a toxic mucus that protects it from larger fish. Its pelvic fins are modified into a sucking disc to hold onto corals. Adult size is about 1.5 inches (4 cm).

Social Behavior: Sedentary and host-specific. These gobies spend their lives nestled between coral branches. They form monogamous pairs that defend their host coral from rivals, but they are entirely peaceful towards fish that swim in the open water.

Coloration and Sexual Dimorphism: Body is pale greenish-blue to light grey, covered with rows of distinct red-to-orange spots on the head and flanks. They are bidirectional hermaphrodites, meaning they can change sex in either direction to form compatible breeding pairs.

Aquarium Setup: Best suited for established SPS reef aquariums of 10 gallons (40 liters) or more. The tank must contain healthy, large colonies of branching stony corals (specifically Acropora) for the goby to live on and lay eggs.

Diet and Feeding: Carnivorous. Feeds on zooplankton, copepods, and occasionally the mucus of the host coral. Feed multiple times a day with very small frozen foods like oyster eggs, cyclops, rotifers, baby brine shrimp, and finely minced mysis.

Water Quality: Requires the high-quality water parameters necessary for keeping SPS corals: stable temperature of 24-28°C (75-82°F), pH of 8.1-8.4, salinity at 1.023-1.025, near-zero nitrates/phosphates, and moderate to high water flow.

Compatibility and Cohabitation: Reef safe, but their presence can cause Acropora corals to retract their polyps or lose tissue where eggs are laid. Keep with small, non-aggressive reef species such as neon gobies, cardinalfish, and small blennies.

Aquarium Breeding: Spawns regularly in aquaria if a pair is established. They clear a small patch of tissue from a coral branch to deposit a ring of adhesive eggs, which the male guards. Raising the tiny, fragile larvae is extremely difficult.

Risks and Diseases: Highly dependent on healthy corals; if the host coral dies, the goby will suffer severe stress. Because it lacks scales, it is highly sensitive to copper-based medications and quick changes in water chemistry.