The Fish Eating Anemone is the largest of the Urticina genus, but is actually the most delicate!

The Fish Eating Anemone Urticina piscivora is a beautiful cold water animal found in the North Pacific. It is the largest of the Urticina anemones, reaching about 8 to 10†(20 – 25 cm) in diameter, but is named for its diet. The genus name “Urticina” is Latin for nettle, which is a stinging plant, and its species name “piscivora” means “fish-eating.” Hence, it is also known as the Fish Eating Urticina.

The beauty of the Urticina anemones has led them to be likened to “flowers of the sea.” Another common name the Fish Eating Anemone is known by is Tealia Anemone, but this name is also associated with all if these colorful anemones. Tealia means “blooming” and is descriptive of these soft-bodied, primarily sedentary marine animals resemblance to flowers. Being richly colored in red shades, with a velvet-looking texture, this anemone is also called the Velvety Red Anemone and Rose Anemone.

Despite its delicate nature, this anemone is true to its name “fish eating.” It does just that, using its strong tentacles to catch small fish and shrimp. Like all anemones, the Fish Eating Urticina use their venomous cells, or nematocyst found in their tentacles, to sting and deflect any possible threats or attacks. But they mostly utilize them for stunning and capturing prey. Despite its large size, however, fish and shrimps can still be quite a large catch for this anemone.

Painted Greenling, Oxylebius pictus, is hosted by the Fish Eating Anemone!
Painted Greenling Oxylebius pictus

This anemone enjoys feasting on small fish, but it is not a predator to all fishes. It’s a fish eating sea anemone that actually plays host to another fish, and this fish is not the typical clownfish or damselfish usually hosted by anemones.

The Fish Eating Anemone has a great relationship with a small fish called the Painted GreenlingOxylebius pictus. The Painted Greenlings will sometimes lie in Fish Eating Anemones. This is much like clownfish do in typical host anemones, and it then uses this anemone for protection. For its part, the Fish Eating Anemone does exactly that, provides protection.

Not much care information has been written about the Fish Eating Anemone, but using similar husbandry as for other cold water anemones is suggested. Some predators of this anemone can be certain nudibranchs, sea stars, and snails.

For more facts about Urticina Sea Anemones, see:
Nettle Anemones

Fish Eating Anemone, Urticina Piscivora

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Two different colored anemones

The Fish Eating Anemone, Urticina Piscivora, does just that…. it will eat fish. If you decide you would like one, your first purchase would be a chiller, since this is a cold water anemone needing temperatures from 55 to 60˚F. If you can find a Painted Greenling, Oxylebius pictus to purchase, this fish from a family from the scorpionfish Order, it will HOST the anemone. This fish will grow to almost 10,” so the tank should be a good size. Avoid purchasing clownfish, since the Fish Eating Anemone will eat them. This is a very cool combo for a species specific cold water tank!

Fish Eating Anemone – Quick Aquarium Care
  • Minimum Tank Size: 50 gal (189 L)
  • Aquarist Experience Level: Advanced
  • Temperament: Semi-aggressive
  • Temperature: 59.0 to 72.0° F (15.0 to 22.2&deg C)
  • Size of organism – inches: 10.0 inches (25.40 cm)
  • Diet Type: Carnivore
  • Suitable for Nano Tank: No

Habitat: Distribution / Background

The Fish Eating Anemone Urticina piscivora was described by Sebens and Laakso in 1978. It is found in waters in the Northern Pacific from La Jolla, Mexico all the way up to Alaska. This anemone is not on the IUCN Red List for endangered species. Some other common names they are known by are Fish Eating Urticina, Tealia Anemone, Velvety Red Anemone, and Rose Anemone.

The Urticina genus is a member of the Aiptasiidae family and currently contains 12 species. General common names the various Urticina anemones are known by include the Mottled Anemone, Painted Urticina, Northern Red Anemone, Painted Tealia, Red and Green Anemone, Northern Red Anemone, Dahlia anemone, and Thick-petaled rose anemone. These common names are often used interchangeably, but there is one generally accepted common name for each species.

Fish Eating Anemones are found in colder waters on rocky reefs. They occur in subtidal areas in the middle and deep reefs. They are usually seen on rocky outcroppings or walls from the low intertidal zone, down to about 160 feet (49 m). They are found solitary or in small groupings.

These anemones use their venomous cells, or nematocyst found in their tentacles, to sting and deflect any possible threats or attacks. But they mostly use their potent sting to immobilize small fish and invertebrates, primarily shrimp. Fish Eating Anemones will not host clownfish, but they will host a small fish called the Painted Greenling Oxylebius pictus. Some predators, can be certain nudibranchs, sea stars and snails.

  • Scientific Name: Urticina piscivora
  • IUCN Red List: NE – Not Evaluated or not listed

Description

The Fish Eating Anemone is the largest member of the Urticina genus. It can grow up to 10†(25 cm) in diameter and up to 8†(20 cm) in height. Its oral disk is crowned with tentacles, and can extend about 10″ (25 cm) across. In the wild, Urticina anemones can live between 60 to 80 years.

This anemone has a cylindrical pedal column with a sticky “foot†at the bottom that they use to adhere to various surfaces. The color of the column and foot can be various shades of orange to red. They also use this foot to move around if conditions are not ideal. They can also move by inflating themselves, detaching from the surface, and then rolling along with any current. They will move to avoid predators like starfish, but in the aquarium it is primarily if they are unhappy with the water conditions or food.

At the top of the column is an oral disc with an opening, or mouth, in the center. The U. piscivora takes food in and expels waste through this opening. The mouth should be closed and tight. It will open when hungry, having an oval look. A gaping mouth is a warning signal that the anemone is not doing too well.

The sturdy tentacles are well spaced on the oral disc. They are situated in 5 or more rows surrounding the mouth. The tentacles are thin at the tip and are solid white, yellow, or orange-to-red. The oral disc surrounds the base of each tentacle in red to pale orange, yet the area around the mouth is similar to the tentacles in color.

  • Size of organism – inches: 10.0 inches (25.40 cm) – They can reach up to 10†(25 cm) in diameter and 8†(20 cm) in height.
  • Lifespan: 80 years – Urticina anemones can live from 60 to 80 years in the wild, probably less in captivity.

Difficulty of Care

The Fish Eating Anemones are the most delicate of the Urticina anemones and can be difficult to care for. These cold water anemones need more specific care than tropical anemones and need perfect treatment from the start. They do have lighting needs and must be kept in a cold water reef. As with most anemones, the tank should be at least 9 months old and stable before adding your new U. piscivora.

When selecting a U. piscivora, make sure the color is good, their mouth is not gaping open, and their foot and tentacles are sticky to the touch. They should also be attached to something. Make sure there is no damage to the foot area, as this is often a result of pulling the anemone off its surface.

To transfer a Fish Eating Anemone from another aquarium, use a thin blunt item like a credit card, gently wiggle it under the foot, slowly nudging it away from the glass. If its attached to a rock, ideally you can simply purchase the rock as well, because these guys can stick hard and may be damaged if removed. If you cannot purchase the rock, while under water, directing water at it or wiggling the rock gently upside down while tickling the foot can sometimes work.

  • Aquarium Hardiness: Difficult
  • Aquarist Experience Level: Advanced

Foods and Feeding

The Fish Eating Anemone is a carnivore. In nature, they use their potent sting to immobilize small fish and invertebrates, primarily shrimp. In captivity hand feed your U. piscivora chopped silversides, fresh chopped fish (from your grocery store), shrimp, krill, and mussels, as well as frozen carnivore preparations.

The Fish Eating Anemones metabolism is not as fast as warmer water anemones. They are cooler water creatures, so usually only need to be fed once a week or twice a month.

  • Diet Type: Carnivore
  • Flake Food: Occasionally – Carnivore formula. Depends on individual tastes of the anemone.
  • Tablet / Pellet: Occasionally – Carnivore formula. Depends on individual tastes of the anemone.
  • Live foods (fishes, shrimps, worms): Some of Diet – From marine sources.
  • Liquid Foods: Some of Diet – Zooplankton.
  • Meaty Food: All of Diet – Sources of marine flesh and frozen/thawed preparations for carnivores.
  • Feeding Frequency: Weekly – Feed them once a week or twice a month.

Aquarium Care

Water changes of 10% bi-monthly or 20% a month are typical. Monitor your water quality for your particular situation and adjust your water changes accordingly. Waste production created by your anemone can be calculated in inches. Basically, every inch of anemone is equal to an inch of fish, so an average-sized Fish Eating Anemone produces a bio-load equivalent to that of about two 4″ fish or one 8″ fish.

Purigen and Poly-fiber are great products to help in maintaining water quality. Purigen is a synthetic polymer that removes soluble and insoluble impurities from water at an exceptionally high rate and capacity, helping to control ammonia, nitrites and nitrates. Additional chemical additives, such Chemi-Pure, GFO, and carbon also help maintain quality water parameters. Poly-fiber can be cut and used in sumps, etc. A good protein skimmer is a must.

Although anemones are not as dependent on calcium as stony corals, magnesium and calcium is still needed to keep the pH and alkalinity stable and within the correct parameters. Additions of trace elements are suggested. Phosphates should be kept around 0.03 or less. Control phosphates with products such as Phosban and the Phosban reactor.

  • Water Changes: Bi-weekly – Water changes of 10% twice a month, or 20% a month are typical.
  • Calcium Levels: 380.0 – 450.0 ppm – Helps to balance alkalinity. Aim for 420 ppm, or 385 ppm if you are using Seachem calcium.
  • Alkalinity Levels: 7.0 – 11.0 dKH – (2.5 to 3.9 meq/L) Aim for 10 dKH (3.5 meq/l) for reef tanks.
  • Magnesium Levels: 1,250.0 – 1,350.0 ppm – Test magnesium levels and adjust before checking Calcium.
  • Strontium Levels: 5.0 – 15.0 ppm – Aim for 8 ppm.
  • Iodine Levels: – .030 to .060 ppm: Control is not recommended.

Aquarium Setup

The Fish Eating Anemone can be kept in an aquarium of 50-gallons or more. The typical reef environment is needed, but it must be a cold water reef. Provide a 6 to 8″ smooth sand substrate and some rock crevices as well as rocky overhangs. They need live rock or some other solid material they can attach to. You can even use submersed bio-balls. Calcium doesn’t need to be as high in cold water, so providing reef rock for calcium is actually not necessary although it is needed to keep the alkalinity and pH stable.

Because bacterial formations take a very long time in cooler water, the most important thing for the reef is mechanical and chemical filtration. Provide a good skimmer and use filter floss and chemical additives, such Chemi-Pure, GFO, and carbon in the filter to help keep the water clean. Chemi-Pure helps remove heavy metals, copper, phenol, ammonia and other nitrogenous waste. It also helps keep the pH at a consistently safe range. Granular ferric oxide, or GFO, helps with phosphate control. Water changes when things get out of normal parameters, so the addition of a refugium with a deep sand bed can help maintain normal parameters, too.

They need a moderate water movement and moderate to high lighting. The temperature can be between 59 to 72° F (15 – 22° C), but whatever temperature you choose, keep it stable as fluctuations can be stressful to the anemone. A chiller will be needed, but this allows you to have both inter-tidal and sub-tidal animals. Acrylic tanks are best for insulating against temperature fluctuations, each 1/2″ will give a thermal barrier of 5° F. Be sure to have all of your pumps covered, most good quality pumps have guards on them.

  • Minimum Tank Size: 50 gal (189 L)
  • Suitable for Nano Tank: No
  • Live Rock Requirement: Typical Amount
  • Substrate Type: Sand – They like a 6 to 8″ smooth sand substrate.
  • Lighting Needs: Moderate – normal lighting – Lighting should be moderate to high.
  • Temperature: 59.0 to 72.0° F (15.0 to 22.2&deg C)
  • Specific gravity: 1.023-1.025 SG
  • Water Movement: Moderate
  • Water Region: Bottom

Social Behaviors

The Fish Eating Anemone is considered semi-aggressive because they can be mobile and split once they are adjusted. It has often been suggested to not put anemones in a reef environment since corals cannot move away from the stinging tentacles. Most of the cold water anemones will stay still if their needs are met. They will move, however, if your lighting is not good or the water quality is not to their liking.

After splitting once they are settled, the Fish Eating Anemones will tolerate their own “clones†and sometimes their own species. All anemones in the tank need to have their own space, otherwise there can be a “chemical†warfare between species. This will usually cause one to not eat, shrink and eventually die. Having excellent filtration and a large tank will usually allow 2 anemones at opposite ends to thrive. You can also build a natural blockade to help prevent them from wandering into each others “spaceâ€.

Fish Eating Anemones are best kept in a species specific display. Keeping corals in the tank can be a risky thing to do because these anemones will multiply acclimated. If attempting to add cold water corals, allow the anemones to settle first. Once they are in place, you can then try placing a coral away from them.

If the tank is very large, keeping larger cold water fish should be fine. Problems occur when keeping small gobies, blennies or other small cold water fish. These can easily become dinner if they wander into the very sticky (more sticky than typical) tentacles of this anemone. Fish Eating Anemones will not host clownfish, but they will host a small fish called the Painted Greenling Oxylebius pictus.

Be cautious with other tankmates, too, as Urticina anemones are known to eat many invertebrates that wander their way. Similar to others in its genus, this anemone may host the Candy Stripe Shrimp Lebbeus grandimanus. This shrimp lives in a commensal relationship with Urticina and is immune to their sting. Some predators, can be certain nudibranchs, sea stars and snails.

  • Venomous: Yes
  • Temperament: Semi-aggressive
  • Compatible with:
    • Same species – conspecifics: Sometimes – They will tolerate their own offspring.
    • Anemones: Threat
    • Mushroom Anemones – Corallimorphs: Monitor – Keep only with other cold water anemones.
    • Leather Corals: Threat – This anemone will quickly multiply and sting tankmates.
    • Zoanthids – Button Polyps, Sea Mats: Threat – This anemone will quickly multiply and sting tankmates.
    • Sponges, Tunicates: Threat – This anemone will quickly multiply and sting tankmates.
    • Shrimps, Crabs, Snails: Monitor – The Candy Stripe Shrimp, Lebbeus grandimanus, lives in a commensal relationship with Urticina anemones and is immune to their sting.
    • Starfish: Monitor
    • Feather Dusters, Bristle Worms, Flatworms: Threat
    • Clams, Scallops, Oysters: Threat
    • Crabs: Monitor – Cool water species only.
    • Snails: Monitor
    • Sea Apples, Cucumbers: Threat
    • Urchins, Sand Dollars: Threat
    • Nudibranch, Sea Slugs: Threat
    • Copepods, Amphipods, Mini Brittle Stars: Monitor
    • Stony Corals: Threat – is aggressive – This anemone will quickly multiply and sting tankmates.
    • Soft Corals: Threat – is aggressive – This anemone will quickly multiply and sting tankmates.

Sex: Sexual differences

No sexual difference in appearance is known.

Breeding / Reproduction

The Fish Eating Anemone can divide in captivity. There is no information on the propagation of cold water anemones, however, but it may be just like other anemones. These cold water anemones reproduce by external fertilization of egg and sperm. When they spawn, they produce larvae that will float away, and eventually finding a spot to land. They then attach and develop a pedal disk that grows into a new anemone.

  • Ease of Breeding: Difficult

Ailments / Diseases

Fish Eating Anemones are pretty durable once they settle in. Problems are pretty minimal unless your lighting, water movement, feeding and water quality are low. Then your anemone will detach to look for “better conditions.†In general, if your anemone moves, it is not happy. Make sure your lighting and water quality is good, and that the food you are offering is to their liking. Some predators include certain nudibranchs, sea stars, and snails.

Availability

The Fish Eating Anemone is generally unavailable to aquarists through retailers. On rare occasions, however, it may be found online.

References


Featured Image Credit: PxHere