Egg Cowrie

Geographical Origin and Habitat: This species is widely distributed throughout the tropical Indo-Pacific, from the eastern coast of Africa and the Red Sea to French Polynesia, southern Japan, and Australia. It inhabits shallow coral reefs and lagoons, frequently found living on or near large colonies of soft corals (such as Sarcophyton and Sinularia) at depths of 2 to 20 meters.

Taxonomy: Belongs to the family Ovulidae, genus Ovula. Although referred to as a cowrie due to shell shape, it is classified within a distinct family from true cowries. It possesses a bilateral muscular mantle that can extend to fully envelop the outer shell, keeping it clean of epibionts and camouflaging the animal.

Social Behavior: A slow-moving, peaceful invertebrate that remains largely cryptic during daylight hours, hiding under ledges or inside deep reef caves. It becomes active at night to forage. It is harmless to fish and other mobile invertebrates, showing no aggressive interactions.

Coloration and Sexual Dimorphism: The shell is smooth, glossy, and pure porcelain white, while the interior is deep purple. The mantle, when extended, is a rich velvet black covered with tiny gold or white spots. There is no distinguishable external sexual dimorphism between male and female individuals.

Tank Setup: Requires an established marine aquarium of at least 200 liters (50 gallons) with stable rockwork. Heavy rocks must be secured, as its large body can easily dislodge loose aquascaping. It is not reef-safe, as it will feed directly on soft corals, which are its primary food source.

Diet and Feeding: A specialized feeder on octocorals. Its diet in captivity must consist of soft corals, specifically from the genera Sarcophyton, Sinularia, and Lobophytum. It is exceptionally difficult to sustain long-term without access to sacrificial soft corals, though it may occasionally accept prepared meaty foods.

Water Quality: Maintain stable marine conditions: temperature 24-26°C (75-79°F), pH 8.1-8.4, specific gravity 1.022-1.025, calcium 400-440 mg/L, and magnesium 1300-1350 mg/L to support shell maintenance. Like most marine invertebrates, it is highly sensitive to copper medications and rapid changes in salinity.

Compatibility and Tankmates: Safe to keep with peaceful fish and stony corals (SPS/LPS), which it does not eat. Do not house with soft corals that you wish to preserve. Avoid tankmates that prey on mollusks, such as large pufferfish, triggerfish, or wrasses, which can damage its mantle or shell.

Aquarium Breeding: Breeding in home aquaria is not documented. In the wild, they produce egg capsules deposited on substrate. The larvae hatch as free-swimming veligers that enter a planktonic stage, making captive rearing extremely difficult and currently impractical for hobbyists.

Risks and Diseases: Highly susceptible to osmotic shock; slow drip acclimation is mandatory. If the mantle remains retracted for extended periods, it is a sign of poor water quality or irritation from nipping fish. Never treat the aquarium with copper-based medications while this snail is present.