---
title: Shrubby Hydroid (Thyroscyphus fruticosus)
scientific_name: Thyroscyphus fruticosus
common_name: Shrubby Hydroid
taxon: Hydrozoans
published: 2026-08-08T08:16:55.424Z
updated: 2026-08-08T09:36:21.631Z
tags: Shrubby Hydroid, Thyroscyphus fruticosus, Hydrozoans, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/stinging/hydrozoans/shrubby-hydroid
---

# Shrubby Hydroid (*Thyroscyphus fruticosus*)

## Quick facts

- **Group:** Hydrozoans (*Hydrozoa*)
- **Size:** colonies to 15 cm tall
- **Depth:** 3-40 m
- **Diet:** Planktivore
- **Activity:** Cathemeral
- **Rarity:** Uncommon
- **Habitat:** Shaded rock, wrecks and overhangs with current
- **Reproduction:** Broadcast spawner, Budding
- **Hazard:** Venomous

## How to recognise it

- stiff branching colony like a small pale shrub
- polyps sit in tiny cups along the branches, visible up close
- grows from shaded rock and wreck metal into the current
- height up to 15 cm

A stiff, pale, branching colony that grows from shaded rock or wreck metal like a small dry shrub, up to about 15 cm (6 in) tall. Look closely and each branch is lined with tiny cups, one polyp to a cup, all facing into the flow.

A hydroid colony is not one animal but a shared body: individual polyps feed, others specialise in defence or reproduction, and all of them draw on the same gut cavity running through the stems. They release free-swimming medusae - small jellyfish - which is the stage that disperses, so a shrub on a wreck can seed a reef hundreds of metres away. Nudibranchs of several families feed on hydroids and store the undischarged stinging cells in their own tissues, so a careful look at a colony like this often turns up the animal eating it. The sting is minor to a diver, though bare forearms brushed along a colony will feel it.

## Also known as

- **Russian:** Гидроид кустистый

## Scientific synonyms

- *Campanularia juncea* Allman, 1876
- *Campanularia thyroscyphiformis* Marktanner-Turneretscher, 1890
- *Lytoscyphus junceus* (Allman, 1877)
- *Sertularia fruticosa* Esper, 1797
- *Sertularia laxa* Lamarck, 1816
- *Thyroscyphus fruticosa* (Esper, 1793)
- *Thyroscyphus vitiensis* Marktanner-Turneretscher, 1890

## Range

Mediterranean Sea, South Pacific Ocean

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/stinging/hydrozoans/shrubby-hydroid)*
*Updated: August 8, 2026*