Tridacna gigas

(Linnaeus, 1758)

Giant Clam, Gigas Clam

Range: Indo-West Pacific Ocean: Thailand to Southern Japan, and south to the Great Barrier Reef and New Caledonia.

Size: 36 inches (90 cm)

Natural Environment: Inhabits shallow bottom reef environments.

General Husbandry: This "Giant Clam" can generally reach about 400 pounds in the wild and attain about 3 feet (90 cm) in length, with the record being 54 inches (137 cm) and over 700 pounds!

Almost always an olive green/dull brown with tiny blue dots. However, and rarely, a pretty green, blue or combination of colors arrives in the trade.

They are also filter feeders and almost constantly filter the water for small particulates. Small specimens, < 2 - 3 inches can be fed a phytoplankton or greenwater supplement at least three times per week, which may encourage their growth. Larger specimens will do extremely well without any additional feedings.

So as not to repeat some of the Introduction to this section, review it for more information on their aquarium husbandry.

Taxonomy:

Kingdom: Animalia

Phylum: Mollusca

Class: Bivalvia

Subclass: Heterodonta

Order: Cardiida

Superfamily: Cardioidea

Family: Cardiidae

Subfamily: Tridacinae

Genus: Tridacna

FYI: Considered a food item throughout the Far East and Indo-Pacific region.

Does not burrow into the substrate.

Cannot close its shell completely.

Experience Level: Intermediate

Diet: Photosynthetic/Omnivore

Temperament: Peaceful

Aquarium Environment: Reef or fish-only aquarium

Coral Safe: Yes

Fish Safe: Yes

Invertebrate Safe: Yes

Acclimation Time: 30 minutes+

Aquarium Hardiness: Moderately hardy

Calcium (Ca): 380 - 430 mg/l

Alkalinity: 2.5 - 3.0 meq/l

Phosphate (PO4): <0.05 mg/l

Magnesium (Mg): approx. 1350 mg/l (relate to specific gravity)

Temperature Range: 72 - 83°F (22 - 28°C)

Minimum Tank Size: 100 gallons

Lighting: PAR 300 - 450+

Water Movement: WM 2

Specific Gravity: 1.023 - 1.025

pH: 8.0 - 8.4

Iodine/Trace Elements Monitor/as necessary to maintain quality seawater.