Fluted Giant Clam/Squamosa Clam

Fluted Giant Clam/Squamosa Clam Tridacna squamosa

Type of Animal:

Lagoons, sheltered patch reefs, sheltered reef flats, sheltered steep walls, rubble areas, coral groves, shallow reefs, intertidal coral areas, outer reef slopes, reef pockets, found on rubble, soft bottoms, sandy bottoms, coral groves, and/or coral


Variably colored mantle, large widely spaced leaf-like fluted scutes (shell edges), small byssal opening, symmetrical shell

Make food for themselves in 4 ways-firstly, they have large amounts of symbiotic single-celled dinoflagellate algae (zooxanthellae) in tissues-due to these clams needing well-lit habitats, algae may make too much food for themselves giving extra carbon/glucose to clam. Secondly, zooxanthellae can be eaten by amoebid cells within host clam. Thirdly, they can absorb nutrients from water. Fourthly, they can act as filter-feeders, straining phytoplankton/zooplankton/detritus/algae w/ gills.

Status in Wild:

Use in aquaculture reducing demand for wild-caught clams

Colonies of 30-40 clams, sometimes found alone as well

Additional Info:

Young: Trocophore
Group: Colony/Aggregation/Bed

50-160 lbs

12 hours

Life Span:
30-70 years in captivity, 150-215 years in wild

Adult: 10-16 in
Young: 2-4 in

Main predators are fish, sea stars, crabs, sea turtles, predatory/parasitic snails, anemones, sea snakes, lobsters, shrimp, bristleworms, fireworms, octopus, burrowing sponges, & clam worms.

They’re very slow growers after reaching maturity.

Reproduction stimulated by lunar cycle, time of day, & presence of other eggs/sperm.

Fairly popular in aquarium trade.

Also called Scaly Clam & Scaled Giant Clam.

Adults use weight to keep themselves in place.

Fun Fact(s):
In many places, these clams considered delicacies & aphrodisiacs. Large shells used to make souvenirs.

Start life as free-swimming larvae, then developing into new larval stage capable of filter-feeding. Develop feet at 3rd larval stage, allowing it to alternately swim/rest. Become juveniles at around 8-10 days old, when they acquire zooxanthellae, starting symbiotic relationship. Juveniles become males at 2-3 years old, eventually becoming hermaphroditic once they reach 5.9-6 in.

Due to being hermaphrodites much of their life, sperm released 1st followed by eggs, avoiding self-fertilization.

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