Crocea clam

Care at a glance

Overview

The Crocea clam is a peaceful, reef-safe clam for a brightly lit reef tank. It is difficult, and best left to experienced reef keepers.

Caring for the Crocea clam

The Crocea clam has the highest light demand of any clam in the trade. It evolved in the shallowest, brightest part of the reef. Give it intense, stable lighting, and place it as high in the tank as the aquascape allows.

Keep it in a tank of 30 gal (115 L) or more. It needs a hole or crevice in solid live rock near the top of the tank to bore into, not open sand. Once it seals itself into the rock, never pry it back out.

It bleaches easily under sudden bright light, so acclimate a new Crocea clam more cautiously than other clams. Float it to match temperature and drip acclimate it slowly. Start it in a shaded, lower-light spot for two to three weeks before working it up toward full intensity.

Hold the water at 75 to 81°F (24 to 27°C) with a pH of 8.1 to 8.4. Calcium, alkalinity and magnesium all need to run high and steady, since it grows a thick shell quickly for its size. Aim for the range other Tridacna want: calcium 400 to 450 ppm, alkalinity 8 to 11 dKH and magnesium 1280 to 1350 ppm.

Like the rest of its family, it hosts photosynthetic zooxanthellae in its mantle. It relies on them for most of its energy and for the raw material to build its shell. Clams under 5 cm benefit from a phytoplankton or greenwater supplement several times a week, on top of what they get from light. Keep an eye out for mantle nippers such as certain wrasses, crabs, shrimp and pyramid snails, which target the exposed mantle tissue.

Good to know

The Crocea clam, Tridacna crocea, is the smallest species in the family Cardiidae, subfamily Tridacninae, far smaller than the derasa or gigas clams. It is the only Tridacna that fully embeds itself in rock, rather than sitting on top of the substrate the way its relatives do. All Tridacnidae, this species included, fall under CITES Appendix II, so exporting live clams or shells across borders requires proper permitting.

In the wild

The Crocea clam lives on shallow reef flats across the central Indo-Pacific. The water there is so shallow that it is sometimes briefly exposed at low tide. It bores fully into coral rock or dead limestone until only its colorful siphonal mantle sits flush with the surface.

Common questions

Related species

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  Noah's clam

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• 

  Squamosina clam

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  Maxima clam

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  Squamosa clam

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• 

  Derasa clam

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• 

  Gigas clam

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