---
title: Fluted Giant Clam (Tridacna squamosa)
scientific_name: Tridacna squamosa
common_name: Fluted Giant Clam
taxon: Clams
conservation_status: LC - Least Concern
published: 2023-12-29T10:12:26.668Z
updated: 2026-08-14T11:57:50.780Z
tags: Fluted Giant Clam, Tridacna squamosa, Clams, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/molluscs/clams/fluted-giant-clam
---

# Fluted Giant Clam (*Tridacna squamosa*)

## Quick facts

- **Group:** Clams (*Bivalvia*)
- **Size:** up to 40 cm
- **Depth:** 1-20 m
- **Diet:** Photosynthetic
- **Activity:** Diurnal
- **Rarity:** Uncommon
- **Habitat:** Reef flats and slopes, resting on the bottom rather than bored in
- **Reproduction:** Broadcast spawner, Protandrous hermaphrodite
- **CITES:** Appendix II
- **Conservation status:** LC - Least Concern

## How to recognise it

- shell with four to six ranks of tall projecting flutes
- sits on the bottom or in a hollow, not embedded in rock
- mantle patterned in blue, green and brown
- shell to 40 cm

A giant clam with tall fluted scales rising off the shell in ranks, up to 40 cm (16 in), sitting loose on the reef rather than sunk into it. The flutes are the field mark: its common neighbor, the Small Giant Clam, bores itself into coral rock and shows only a slot of mantle.

The mantle is a farm. Inside it live symbiotic algae, and the clam has evolved a lens system to feed them - iridescent cells that scatter incoming light sideways and downward so it reaches the algae at survivable intensities instead of burning them. The colors a diver photographs are the optics of that arrangement, and no two clams carry the same pattern.

The algae supply most of the clam's food, which is why giant clams live in clear shallow water and cannot be moved deeper. Filtering is a supplement rather than a livelihood.

It starts male and becomes female with size, so the large individuals in a population are the ones producing eggs - the ones fisheries take first. Every giant clam is listed on CITES Appendix II, and populations here are thin compared to what the reefs once held.

## Also known as

- **English:** fluted clam, giant fluted clam, fluted giant clam, giant clam
- **French:** Bénitier
- **German:** Schuppen-Riesenmuschel, Schuppige Riesenmuschel
- **Portuguese:** Bivalve
- **Japanese:** ヒレシャコガイ
- **Russian:** Гигантская чешуйчатая тридакна

## Scientific synonyms

- *Tridacna (Chametrachea) squamosa* Lamarck, 1819
- *Tridacna lamarcki* Hidalgo, 1903

## Range

Indian Ocean, Madagascar, Mozambique, Republic of Mauritius, South Africa, Tanzania

---

*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/molluscs/clams/fluted-giant-clam)*
*Updated: August 14, 2026*