---
title: Orange-spotted Okenia (Okenia rhinorma)
scientific_name: Okenia rhinorma
common_name: Orange-spotted Okenia
taxon: Nudibranch
published: 2026-08-26T12:52:27.515Z
updated: 2026-08-26T13:26:00.661Z
tags: Orange-spotted Okenia, Okenia rhinorma, Nudibranch, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/molluscs/nudibranch/orange-spotted-okenia
---

# Orange-spotted Okenia (*Okenia rhinorma*)

## Quick facts

- **Group:** Nudibranch (*Nudibranchia*)
- **Size:** up to 1 cm
- **Diet:** Carnivore
- **Activity:** Cathemeral
- **Rarity:** Rare
- **Habitat:** Encrusting bryozoan and ascidian growth on rubble and rock
- **Reproduction:** Simultaneous hermaphrodite, Egg layer

## How to recognise it

- rhinophores set far back on the body, almost touching the gills
- white with scattered orange spots
- one centimeter, which is the main reason it goes unrecorded
- slim and tapered rather than the usual flat dorid oval

Every dorid on this reef is laid out the same way, and it is a sensible way to be laid out. The two chemical sensors go at the front, because that is the end that arrives first and needs to smell what is ahead. The gill plume goes at the back, as far from the mouth and the sensors as the body allows. Front to back, sense to breathe, on hundreds of species.

This genus moved the sensors backward until they nearly touch the gills.

That is what the species name records and it is the whole identification: a small white animal with orange spots whose rhinophores are sitting in the wrong place, crowded up against the gill plume near the rear. Why it is arranged that way is not settled. What is clear is that the usual layout is not compulsory, which is worth knowing about a body plan that otherwise looks fixed.

The rest is a matter of size. It is one centimeter (0.4 in) long and lives on the encrusting film that coats rubble and dead coral, the bryozoan and ascidian mats that most divers never resolve as anything but fuzz. Animals that small, on food that unremarkable, get described late: this one waited until 2007, and it was named by Bill Rudman, whose Sea Slug Forum did more than any journal to make this group findable for people with cameras.

To see one you have to be looking at a square hand of rubble rather than at the reef.

## Also known as

- **Japanese:** ツノウミウシ
- **Russian:** Окения оранжевопятнистая

---

*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/molluscs/nudibranch/orange-spotted-okenia)*
*Updated: August 26, 2026*