Red-eyed Medusa

Author: Anouk Mock

Photos: D. Young

Common name:  Red-eyed Medusa, Red-eyed jelly, Bell medusa, Penicillate jellyfish

Scientific name: Polyorchis penicillatus 

Identification:  The Red-eyed Medusa is a hydrozoan jellyfish. Its size range is 2-5 cm.  At the lower rim of the bell there are around 100 evenly spread tentacles. The tentacles can expand to double in length or contract until they’re only a few millimeters long.  On the base of each tentacles is a distinctive red “eye” spot. The finger-like gonads hang down from the subumbrella surface and the there are four radial canals with their branching diverticula that radiate down the sides of the bell from the gastric vascular cavity.  They are transparent but sometimes the internal organs have a yellow, yellow-brown, reddish-brown to purple colour.  This, in part, may be due to the colour of the food they have ingested.  The photos here show the distinct orange colour of the brine shrimp in the manubrium, the radial canals and diverticula, and the gonads have taken on the same hue. 

Habitat:  The Red-eyed Medusa is found from the Aleutian Islands, Alaska to the Gulf of California and Mexico. They are sometimes seen in the open ocean but their usual habitat is in coastal areas, nearshore and especially in shallow bays with eel grass beds.  The one’s shown here were among dozens found nearshore in the late summer in Tsehum harbour near Victoria, British Columbia. 

Life cycle:  The Red-eyed Medusa are either male or female.  They spawn synchronously right after it becomes dark and the female can produce up to 10,000 eggs per day.  The spawning event is known to last only 10 minutes.  The fertilized eggs eventually become a ciliated, non-feeding planula larvae that settles on a substrate where they develop into a small polyp stage.  The anemone-like polyps can live here for several years. When the condition is right, they begin to develop into little medusas. That’s the reason for them to be common in one year and rare in other years.

The life span is unknown but is thought to be about a few months.  The adults that occur in Tsehum Harbour near Victoria are apparent in large numbers inshore around July though September and have been kept alive in a kreisel aquarium feeding on brine shrimp until October when their health diminished. 

Prey:  The Red-eyed Medusa floats above its prey and expands its tentacles to their full length. Then it floats gently downwards, trapping its prey between its tentacles.  If they have a lot of food in their tentacles they pull them all up to their manubrium in what has been described as crumpling.  They feed on small invertebrates, zooplankton, small crustaceans and worms.

Fun Facts:

  • They only see light 
  • The species has declined in BC, but the reason is unknown
  • Their hunting method is called sink fishing
  • The older jellyfishes have more tentacles.
  • They migrate to the surface during the night.
  • They are not toxic t0 humans
  • The red-eyed Medusa is a hydromedusa, not a true jelly (scyphozoan)

A tentacle loaded with cnidocytes from the Red-Eyed Medusa (Polyorchis penicillatus).  The fired nematocysts can be seen in the centre of the photo.


Polyorchis penicillatus | The Oregon Institute of Marine Biology. (n.d.). The Oregon Institute of Marine Biology. Retrieved February 11, 2024, from

Red-eyed Medusa | Online Learning Center. (n.d.). Aquarium of the Pacific. Retrieved February 11, 2024, from

Ross, C. (2022, July 15). Red-Eye Medusa (Jellyfish) – Crosscurrents Kayak. Crosscurrents Kayak. Retrieved February 11, 2024, from

Red-Eyed Medusa of Oregon / Washington Coast is Immortal In a Way. (2020, October 18). Oregon Coast Beach Connection. Retrieved February 11, 2024, from

Burrowing Green Anemone

Scientific name:  Anthopleura artemisia (Cribrina artemisia)

Author:  Elliot Scott-Bigsby

Identifying features:     The Burrowing Green Anemone’s crown is up to 10 cm (4.0 in) in diameter, with a column of up to 25 cm long (9.8 in). It is often found partially buried in sand of shells, with the exposed part a green colour, with bands of white. The column is pink or white, and its base will attach itself to rock, or something similarly sturdy, underneath the sediment. It may be found with all tentacles displayed and visible, withdrawn, appearing as an unclear shape, or possibly as a puckered hole in the sand.

Geographical range:     Found from Alaska to southern California, and are especially common around Juneau, Alaska.

Habitat:     Usually in protected bays, preferably with rocks and cobble covered with a layered of sand. It’ll also occasionally be found around open coasts. It’s depth will be between low intertidal and subtidal zones, up to about 30 m in depth.

Food (Prey):     They’re carnivorous and stationary in shallow areas, making their primary prey small crustaceans, but they will attempt to capture and eat whatever creatures touch their tentacles.

Predators:     It is prey to nudibranchs and small fish.


Cowles, D. (2004) Anthopleura artemisia. Retrieved from

Fretwell, K. and Starzomski, B. (2013) Buried green anemone, moonglow anemone, burrowing anemone, Anthopleura artemisia. Retrieved from

Piazzola, C.D. and Hiebert T.C. (2015) Anthopleura artemisia. Retrieved from

Sarsia spp. 

Author: Bridget Laver

Size: bell is 6-20mm tall. 

The Sarsia jellyfish has a bell height of 6mm – 20mm that is marked with 4 tentacles and 4 very narrow radial canals.  At the base of each tentacle is a distinct ocelli.   It is transparent and colourless, but its other body parts may have tints of red, blue, tan, orange or green. The manubrium of the jellyfish is long compared to the overall size of its body and for most of its length is surrounded by gonad tissue.  They are fast swimmers and have a comical appearance as they move through the water with their long manubrium trailing beyond the bell.  Similar to other hydrozoans they feed passively on crustacean zooplankton that are captured in their extended tentacles. A number of species of Sarsia may live in the same area but even specialists may have difficulty identifying which species is which.  They are typically found near the surface along the coast from central California to the Bering Sea.  


Wrobel, D., & Mills, C. (2003). Pacific Coast pelagic invertebrates: A guide to the common gelatinous animals. Monterey, CA: Sea Challlengers.

(n.d.). Retrieved from

The Clinging Jellyfish

Authors: Solace and Zaijha

Photos by D. Young

Scientific name: Gonionemus vertens

Size: bell is 1.5 to 2.5cm in diameter

Gonionemus vertens, also known as the Clinging Jellyfish, is an invasive species in many oceans. The medusae found in the Pacific Northwest do not have a painful sting, but those found in the Pacific near Russia are very venomous with a potent venom that can cause muscle cramps, chest tightness and a swollen throat when stung.

Identifying features:

The clinging jellyfish is very small and has up to 80 tentacles. Its bulb is only around 1.5 to 2.5cm in diameter. Inside the bulb is the stomach and radiating outwards are four distinct orange to yellowish-tan gonads.


The Clinging Jellyfish is a native species to the Pacific Northwest Sea and Pacific Northeast Sea.  It is an invasive species to the Arctic Sea, Atlantic Northeast Sea, Atlantic Northwest Sea, as well as the Mediterranean and Black Seas. This jellyfish tends to favour sheltered harbours with weak tide in temperate to warm temperate areas. The reason why this jellyfish is called the Clinging Jellyfish is because of its habit of clinging onto kelp, Eel-grass and shells.  In our kreisel aquarium the Clinging Jellyfish was observed holding on to Eel-grass (Zostera marina) for long periods of time while resting.  It periodically would swim with strong bursts of speed and then float freely with its tentacles extended while feeding before clinging back onto the eel grass.


Gonionemus  vertens usually feeds on smaller crustaceans like copepods. Small fish are also part of their diet along with various larvae. The Clinging Jellyfish uses a passive hunting behaviour that involves spreading out its tentacles and waiting for its prey to come into contact with it and then pulling in the wounded prey to eat.


Hagan, Melissa. “California Non-Native Estuarine and Marine Organisms (Cal-NEMO).” California Non-Native Estuarine and Marine Organisms (Cal-NEMO) System,\

Wrobel, D., & Mills, C. (2003). Pacific Coast pelagic invertebrates: A guide to the common gelatinous animals. Monterey, CA: Sea Challlengers.

(n.d.). Retrieved from

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Hanging Stomach Jellyfish

Scientific name: Stomotoca atra

Size: 25mm wide bell

Distribution: The Bering Sea to Southern California.  Commonly seen in the summer in Puget Sound, British Columbia, and Alaska.

Author: Julia Traill

This hydromedusa is characterized by a long manubrium that hangs below the bell with regularly folded gonads attached to it that are a light gray to tan in colour.  It has 2 large tentacles on each side as well as 80 small marginal tentacles encircling the bell.


Wrobel, D., & Mills, C. (2003). Pacific Coast pelagic invertebrates: A guide to the common gelatinous animals. Monterey, CA.

Leuckartiara spp.

Author: D. Young

Common Name: A member in the family Pandeidae within the order Anthomedusae of the subclass Hydromedusae.

Scientific NameLeuckartiara spp.

Total Length of Specimen in photo is 3cm (30mm).

Nanomia bijuga

Common Names: Siphonophore

Scientific Name: Nanomia bijuga

Size Range: Up to 30cm in total length

Nanomia bijuga belongs to the order Physonecta within the subclass Siphonophorae within the class Hydrozoa.

It is a predator that represents a colony of many genetically identical individuals called zooids that make up the whole.  It has a pigmented gas filled float called a pneumatophore at its tip.

Please come back – more information will be posted soon on this fascinating siphonophore!

Photos by D. Young

Nanomia bijuga collected in Cadboro Bay, Victoria, British Columbia. This is the position they are normally found in when at rest in the water, however, they can swim quite fast and may be close to horizontal at these times.

Crystal Jelly

By Julia Traill

Size: Bell Diameter can be up to 25cm, though the size of this jellyfish can vary depending on where it is found.

Scientific name: Aequorea victoria

Identifying Features: They have many radial canals with more than one-hundred and fifty sticky tentacles that are laced with toxins that allow it to easily catch its varying prey. It also has gonads that follow along their radial canals. They are mostly transparent but under ultraviolet light there is a bioluminescent green ring around the bottom of their umbrella.

Habitat: The hydromedusae can typically be found from spring to autumn in the Pacific waters off the coast of North America, from the Bering Sea to southern California.

Predators: Predators of the Crystal jellyfish are typically other vicious jellies such as the Lions Mane Jellyfish and others. Another technical predator of theirs would be humans, as they are used to conduct research in gthe medical field.

Food: For the most part these guys consume other soft bodied organisms like themselves. A few classes that they may eat are hydromedusae, ctenophores, polychaetes, and appendicularians. Crystal jellyfish have the ability to consume other jellyfish that are twice their size and appear to prefer Comb Jellies over others. They are also known to be cannibalistic so when one keeps them they must ensure there is enough room.

Reproduction: Crystal jellyfish reproduce just like any other possible jellyfish as they can do so both sexually and asexually. They reproduce year-round leading to there being new young Medusae a minimum of every two days. Their polyps also tend to live in colonies, and can live up to more than 2 years.

Fun Facts:   Aequorea victoria produces the green fluorescent protein (GFP). This species is rarely bioluminescent in nature but by placing it under a black (UV) light the GFP can be observed. Osama Shimomura first discovered GFP and in 2008 he and his colleagues Roger Tsien and Martin Chalfie were awarded the 2008 Nobel Prize in Chemistry for both the discovery and development of the green fluorescent protein. It is important to note that many online sources continue to show unrelated species reflecting green light and inaccurately state it is this species bioluminescing. The species was first described by Murbach and Shearer in the Annals and Magazine of Natural History in 1902 (originally named Mesonema victoria). They indicate that they were “collected in considerable numbers at the entrance of Victoria Harbour and in Puget Sound”. The specimens photographed and used in these videos were also collected off of Victoria, British Columbia.

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Short Plumose Anemone

By Fraser Evans

Common name: Short Plumose Anemone

Scientific name: Metridium senile

Size: Roughly 4 inches

Identifying Features: The Plumose Anemone is usually short from about 2 inches to 4 inches but can get bigger. They’re commonly white or off orange in colour but depending on their living conditions the colours can become bright orange. The tentacles on the anemone are typically transparent but can be off white or orange.

Habitat: Anemones broadly can live in many conditions or habitats. From the tidal zone to up to 100 metres deep you can find these beautiful creatures. Though their preferred locations are exposed sites such as piers, walls, ropes docks or big rocks. Contrary to most sea creatures Plumose Anemones don’t mind brackish water. You can find these critters all over the oceans of the world but especially Alaska to southern California and the other side of North America on the Atlantic coast. Anemones also can be a habitat for other fish such as clown fish with a symbiotic relationship.

Predators: Not many animals attack the Plumose Anemone. In some cases star fishes have been known to eat large anemones. Also nudibranchs commonly eat the Plumose. When anemones are touched they will shrivel up as a defense mechanism.

Food: When small plankton, jellyfish, zooplankton or other small sea critters float by the anemone will reach out with its tentacles and use the nematocyst to poison the prey before proceeding to eat it. The anemones mouth and anus are the same.

Reproduction: Metridium can reproduce either sexually or asexually. Asexually it reproduces by pulling itself into two parts or ripping off pieces of itself and letting these turn into small anemones.  Sexually Plumose will reproduce by releasing its sperm or egg into the sea out of its mouth. Then the little fertilized eggs will grow into larvae which metamorphose into baby anemones.

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Painted Anemone

Authors:  Michael Adams and Daniel Barnaby

Common Name: Painted Anemone

Scientific Name: Urticina grebelnyi

Identifying Features

Urticina grebelnyi can be identified by the pink to white color’s on it’s tentacles, as well as raised bumps, referred to as non-adhesive vesicles, on it’s pedal column. Unlike the similar looking species Urticina crassicornis, that U.grebelnyi is often mistaken for, the column of U. crassicornis is smooth while that of U. gregelnyi has the raised bumps. They vary in color and often have green to light yellow patches covered in red blood-like markings. They have many tentacles that are banded red.


The Painted Anemone lives on the Pacific and north Atlantic coast in shallow and mid-tidal areas and under ledges and crevices. They can be found in small groups as well as large colonies that form carpets on the floor of the ocean.


Almost all anemones are carnivorous and using their tentacles they paralyze and consume any bypassing prey. U.grebelnyi in particular eats shrimp, krill, mussels, and fish.


The Painted Anemone’s natural predators are various species of nudibranches, sea stars, and snails. However it’s not completely defenseless. The tentacles that it uses for catching prey can also be used in self-defense, poisoning it’s enemies in time for it to escape using it’s pedal.

Life Cycle

When anemones reach adulthood the males release sperm and the females release eggs into the water.  The gametes travel in the current where the sperm fertilize the eggs. The fertilized egg then developes into a zygote, and then into a planula, a free-floating larval form of the anemone. The planula will settle on a rock or other solid surface where it grows into a polyp. The polyp looks much like the adult though it is smaller. With enough nutrition it will then grow into an adult, walking on it’s pedal to avoid predators or move to a preferred location and catching prey with it’s fully developed poison tentacles.

Photos by Michael Adams and David Young

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