Crocea Clam

Photo: Wikimedia Commons (CC BY-SA)

Tridacna crocea

Identification	The smallest of the commonly kept giant clams, with a compact, deeply ribbed shell. Mantle coloration is vivid and highly variable — electric blue, purple, orange, gold, and green morphs are common in the trade. Distinguished from Maxima by its smaller size and habit of boring into live rock and coral substrate.
Maximum Length	6 inches (15 cm)
Origin	Indo-Pacific — Indonesia, Philippines, Micronesia, and the western Pacific; typically found in shallow reef flats at 1–10 feet depth
Minimum Tank Size	30 gallons; requires high-intensity lighting
Reef Compatibility	Yes — completely reef safe

Behavior

The Crocea Clam is notable for its unique habit of boring into and anchoring within live rock or coral substrate — a behavior not seen in most other Tridacna species. In the aquarium, provide a piece of live rock rubble or porous rock for it to settle into. It is the most light-demanding of all commonly kept clam species and should be placed in the highest-light zone of the tank. A healthy Crocea will spread its mantle wide and track toward the light source.

Diet & Feeding

Photosynthetic — derives the majority of nutrition from zooxanthellae under intense reef lighting (300+ PAR recommended at placement depth). Supplement with phytoplankton dosing in lower-nutrient systems. Passive filter feeding on fine particulates provides additional nutrition.

Cautions

Highest light requirements of any Tridacna species — insufficient lighting causes rapid decline. Will bore into and potentially damage live corals if placed directly on SPS colonies. Position on rock rubble away from prized corals. Protect from mantle-nipping fish.