---
title: Giant Honeycomb Oyster (Hyotissa hyotis)
scientific_name: Hyotissa hyotis
common_name: Giant Honeycomb Oyster
taxon: Oysters
published: 2026-08-04T10:47:54.574Z
updated: 2026-08-20T17:09:45.804Z
tags: Giant Honeycomb Oyster, Hyotissa hyotis, Oysters, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/molluscs/oysters/giant-honeycomb-oyster
---

# Giant Honeycomb Oyster (*Hyotissa hyotis*)

## Quick facts

- **Group:** Oysters (*Ostreida*)
- **Size:** up to 30 cm
- **Depth:** 3-50 m
- **Diet:** Filter feeder
- **Activity:** Cathemeral
- **Rarity:** Common
- **Habitat:** Reef walls, drop-offs and coral heads

## How to recognise it

- very large and heavy - the biggest oyster on the reef
- shell wall chalky and honeycombed with tiny cavities
- coarse radial ribs ending in broad rounded teeth

The largest oyster found on coral reefs, reaching about 30 cm (12 in) and weighing several kilograms. The shell wall is thick and chalky, and a broken edge shows the structure the name refers to: the calcite is riddled with tiny gas- and fluid-filled cavities, giving it a honeycombed, foam-like texture. Outside, coarse radial ribs end in broad rounded teeth where the valves meet, so the closed gape runs in a heavy wavy line. Live animals are almost always overgrown by sponge, coralline algae and ascidians, and the mantle edge showing in the gape is dark brown to purple-black.

Individuals cement themselves into reef walls, drop-offs and the flanks of coral heads, often set so deeply into the surrounding growth that only the gape is visible - which is how most are found. Depth runs from about 3 m down to 50 m (165 ft), with the larger animals deeper. It filters plankton and organic particles and can close with enough force to hold shut against a prying blade. Growth is slow and individuals are long-lived, so the biggest shells on a Red Sea reef represent decades in the same spot.

## Also known as

- **English:** giant honeycomb oyster, Giant Foam Oyster, Coxcomb Foam Oyster
- **Italian:** Ostrica a nido d'ape, Ostrica del reef, Ostrica favo gigante
- **German:** Große Zackenauster, Riesen-Zackenauster
- **Spanish:** Ostión de Piedra, Ostra de panal
- **Czech:** ústřice lamelová
- **Japanese:** シャコガキ
- **Chinese:** 硨磲牡蠣
- **Russian:** Гигантская сотовая устрица
- **KO:** 벌집굴

## Scientific synonyms

- *Mytilus hyotis* Linnaeus, 1758
- *Ostrea hyotis* (Linnaeus, 1758)
- *Ostrea radiata* Lamarck, 1819
- *Pycnodonta hyotis* (Linnaeus, 1758)
- *Pycnodonte hyotis* (Linnaeus, 1758)

## Range

Belize, Caribbean Sea, Gulf of Mexico, Lesser Antilles, Puerto Rican Exclusive Economic Zone, Republic of Mauritius, South Africa

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/molluscs/oysters/giant-honeycomb-oyster)*
*Updated: August 20, 2026*