Tridacna crocea (Crocea Clam) Care Guide
Tridacna crocea is the smallest giant clam, a boring Indo-Pacific bivalve with a vivid mantle that depends on intense reef lighting.
Compiled by Aquairi from published sources · Published · Updated
Overview
Tridacna crocea is the smallest member of the giant clam subfamily Tridacninae, reaching about 15 cm in shell length. Its mantle shows shades of blue, green, purple, gold, orange or brown, often patterned with spots, stripes or squiggles, while the shell valves are greyish-white. It is known as the boring clam because it embeds itself into massive corals and rock.
Taxonomy
- Family: Cardiidae
- Subfamily: Tridacninae
- Genus: Tridacna
- Scientific name: Tridacna crocea
Habitat
The species is native to the Indo-Pacific, ranging from Malaysia, Vietnam and Japan to Indonesia, the Philippines, Palau, New Guinea, Australia, the Solomon Islands and Vanuatu. It is typically found embedded in massive corals on shallow, well-lit reefs.
Tank requirements
- Minimum tank volume: 150 L
- Temperature: 24-26 C (75-79 F)
- pH: 8.1-8.4
- Carbonate hardness (KH): 8-11 dKH
- Calcium: 380-450 ppm
- Magnesium: 1280-1350 ppm
- Specific gravity: 1.024-1.026
- Lighting: intense reef lighting
- Lifespan: 10-30 years
Diet
Like other giant clams, Tridacna crocea hosts symbiotic zooxanthellae in its mantle and derives most of its energy from their photosynthesis, supplemented by filter feeding. This reliance on light means it requires strong reef illumination, while stable calcium, alkalinity and magnesium support shell growth.
Compatibility
It is peaceful and reef-safe among calm reef fish. Mantle-nipping species such as angelfish, triggers and pufferfish should be avoided, as should aiptasia anemones that can sting the mantle.
Conservation status
IUCN Red List: Least Concern. The species is listed on CITES Appendix II, regulating international trade. It may now be locally extinct in Guam and the Northern Mariana Islands where it formerly occurred.
Breeding the Crocea Clam (Tridacna crocea)
Overview
Tridacna crocea is the smallest clam in the subfamily Tridacninae, reaching a maximum shell length of about 15 cm. It bores into massive corals and rock, wearing the outer valve surface smooth, and is native across the Indo-Pacific. It nourishes itself largely through symbiotic zooxanthellae, which is why it demands intense reef lighting. It is listed as Least Concern by the IUCN and on CITES Appendix II.
Sexing
Giant clams are protandrous hermaphrodites: individuals mature first as males and develop functional female organs as they grow larger, so a mature clam carries both sexes. Individuals cannot be reliably sexed externally, and reproduction relies on multiple clams spawning together rather than on a sexed pair.
Conditioning
Healthy growth depends on strong reef lighting to support the zooxanthellae plus stable calcium, magnesium and alkalinity for shell deposition. In aquaculture, broodstock are conditioned under optimal light and water quality before spawning is induced; a home display maintains the animal but is not used to trigger reproduction.
Spawning & Larvae
As a broadcast spawner, the clam releases sperm and then eggs into the water, with timing tied to the lunar cycle and the presence of gametes from other clams. To avoid self-fertilization, sperm is released before eggs. Fertilized eggs develop into a trochophore larva within about 12 hours, then a shelled veliger; after roughly a week the larva settles and gradually acquires zooxanthellae from the surrounding water. Hatcheries replicate this by inducing spawning and rearing larvae through settlement.
Common Challenges
- Home reefs do not provide the open-water spawning cues or larval conditions for reproduction.
- Free-spawned gametes and planktonic larvae are lost to filtration and predation.
- Settled juveniles must acquire zooxanthellae from the environment.
- CITES Appendix II listing regulates international trade in clams and their shells.