---
title: Sea Walnut (Bolinopsis vitrea)
scientific_name: Bolinopsis vitrea
common_name: Sea Walnut
taxon: Comb jellies
published: 2026-08-10T20:57:59.119Z
updated: 2026-08-10T21:16:38.327Z
tags: Sea Walnut, Bolinopsis vitrea, Comb jellies, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/comb-jellies/sea-walnut
---

# Sea Walnut (*Bolinopsis vitrea*)

## Quick facts

- **Group:** Comb jellies (*Ctenophora*)
- **Size:** up to 10 cm
- **Depth:** 0-60 m
- **Diet:** Planktivore
- **Activity:** Cathemeral
- **Rarity:** Rare
- **Habitat:** Open water, often near the surface at night
- **Reproduction:** Broadcast spawner, Simultaneous hermaphrodite

## How to recognise it

- oval glassy body with two large lobes at the mouth end
- eight comb rows running lengthwise, flickering with color
- no trailing tentacles visible
- up to 10 cm

An oval of clear jelly with two large lobes flanking the mouth, up to 10 cm (4 in) long, so transparent that in daylight it registers as a distortion in the water rather than as an animal. At night a torch turns it on: the eight comb rows fire light down their length in a rolling wave of color.

The lobes are the trap. Small plankton drifting between them is drawn in on ciliary currents and passed to the mouth, so the animal feeds by holding a soft funnel open as it moves. It has no stinging cells at all, which is the standing difference between comb jellies and everything that looks like them.

Members of this family are also famous for what they did in the Black Sea: a close relative arrived in ballast water, met no predators, and ate the plankton that the anchovy fishery depended on, contributing to its collapse. A harmless-looking bag of glass turns out to be one of the most consequential invasive animals on record.

## Also known as

- **English:** Bolinopsis comb jelly, lobate comb jely
- **German:** Lappenqualle
- **Portuguese:** Carambola-do-mar-vidro, Ctenóforo
- **Russian:** Болинопсис стеклянный

## Scientific synonyms

- *Bolina hydatina* Chun, 1879
- *Bolina vitrea* L. Agassiz, 1860
- *Bolinopsis hydatina* (Chun, 1879)

## Range

North Atlantic Ocean

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/comb-jellies/sea-walnut)*
*Updated: August 10, 2026*