Zebra Moray Eel

The Zebra Moray Eel is the absolute best captive kept eel that can be housed with small fish, however they do need a large tank!

Zebra Moray Eels have an overall color that can range from a medium brown to a dark brown or even black.  They have much thinner vertical white to pale yellow bands that encompass their bodies, giving them that “zebra” motif look.  Some odd ball individuals can have even colors of white and brown.  Juveniles have the same appearance, except their bodies are not as thick and muscular as adults and their face is smaller.  They have a rounded snout and molar like teeth placed close together, which perfect for crushing hard shelled prey.  These teeth are arranged in 2 to 3 rows on each jaw, including several rows on the roof of their mouth.  The Zebra Moray has one continuous dorsal fin and one continuous pelvic fin, but lack pectoral fins and tail fins.  They have elongated, flexible gill coverings, but lack bony gill plates and their entire body is scaleless.  Zebra Moray Eels have an excellent sense of smell, with 2 tube like appendages on their nose and two holes at the top of their head.   This amazing ability makes up for their poor vision. These crustacean eaters they grow up to 4.9 feet (1.5 m).  Zebra Moray Eels can be kept by intermediate aquarists, since beginners typically do not have very large tanks, and dedication to a fish that can live over 20 years.

The Zebra Moray has more jaw power for crushing crustaceans than other morays of similar size.  Zebra morays will bump their nose into possible prey to decide if it is on the menu.  That being said, even though they are the most docile, you may be accidentally bitten because they cannot see very well and may think your hand is a tasty crab and a “taste” can be painful!   Speaking about food, they have been recorded in the wild, eating up to 3.6 times their body weight per year!  This may give us an idea of how much to feed them every week.  When feeding, they will swallow smaller crabs/shrimp whole, and larger crabs will be held down by their massive body, as they break off their claws and legs one by one; a noise that can be heard outside the aquarium!  They do not use the knotting method to break up their prey, but may rotate to snap of the legs or claws of larger crabs.  Morays respirate by opening and closing their mouths, forcing water down their throat and over their gills, which can look quite menacing! 

Use a feeder stick to offer them varied marine mollusk and crustacean flesh.  Overfeeding eels can cause fatty deposits on the liver.  Make sure rock work is heavy and tightly secured with cable ties, non-toxic zip ties or another means, and sitting directly on the bottom of the tank, not on top of sand.  Do not use decorations made of fiberglass, since it will cause sores to form on their skin.  Due to their lack of scales, do not use medications that have copper or organophosphates (masoten, dylox, Dipterex, Neguvon, and Malathion).   If you find your Zebra Moray Eel dried up on the floor, quickly put them back in the tank, since they shed their outer slime cover to protect themselves.  Be patient since this can take several hours for them to revive!

Zebra Morays will not bother even the smallest fish.  However, they will eat any mollusk or crustacean in the tank.  Cleaner shrimps are not usually eaten if they were in the tank first.  When using a feeder stick, they can learn to wait for food!  Morays will not bother corals, but their movements can irritate, topple or break delicate corals; and topple rocks onto the corals or themselves.  That being said, they are the most clumsy of the eels, and shouldn’t be housed with corals unless the tank is very large and corals are near the top.  The copious amounts of body slime and waste that this fish produces makes it very hard to keep the water quality high, in the presence of corals, so only attempt if the tank is at least 500 gallons.  If housing with another eel or other tank mates, the tank should be much larger than the minimum tank size listed below. 

Minimum tank size is 250 gallons (1000 liters), due to the high level of waste production.  Although older literature states 75 gallons as the minimum, it is commonly accepted that tanks should be much larger.  A good rule of thumb may be 50 gallons per foot of eel.  If you happen to obtain a full grown Zebra Moray Eel that has only grown to 3.3 feet, then a tank that is 150 gallons may be possible.  Eels love PVC pipe because it is nice and dark and can be cut to their length!   Although they are not as escape prone as other morays, still provide a tight fitting lid that is heavily weighted.   The issue that comes with a solid, tightly fitted lid, is the need for an external source of oxygen, such as an air pump.  A sealed saltwater tank needs to have the air above the water surface and the lid oxygenated.  Without this added air, carbon dioxide will build up in this space, causing low pH, which can kill your tanks inhabitants, including the eel.  Use open tubing so the bubbles are large so they don’t turn into micro bubble which can irritate them and interfere with oxygen exchange.   Strong water movement helps with filtration.  Any light is acceptable as long as the inside of their hiding spot is completely dark.  They will swim near the bottom of the tank.  

For more Information on keeping marine fish see:
Guide to a Happy, Healthy Marine Aquarium

Habitat: Distribution / Background

The Zebra Moray, Gymnomuraena zebra, was first described by Shaw in 1797.  The only common names they have been known for is the Reticulated Moray, Zebra Moray, and Zebra Eel, all of which describe their patterning.  The genus name, Gymnomuraena perfectly describes the Zebra Moray.  “Gymnos” means naked in Greek, and “muraena” means morey eel in Latin.  This eel was once put in the Echidna genus.

Of the 200 species of moray eels on record, there are only about 12 or so that are suitable for home aquaria and the Zebra Moray is one of them due to their docile nature!

Distribution – Habitat:
The Zebra Moray is found in the Indo-Pacific; from the Red Sea and East Africa to the Society Islands, and north to the Ryukyu and Hawaiian Islands and south to the Great Barrier Reef of Australia.  In the Eastern Central Pacific, they are found on Baja California’s southern coast, then south toward Mexico, Guatemala, northern Columbia and the Galapagos Islands.  Their preferred habitats are rocky, sandy and coral reefs located on fringing coastal reefs, fore-reef slopes, and reef faces; where they hide in crevices and under ledges.  They are found from 10 to 127 feet (3 to 39 m), and in surge zones they are found at 127 feet (39 m).   Main foods are xanthid crabs, but will eat other crustaceans, mollusks and sea urchins. 

These eels are found alone in the wild, however they can be found sharing a hideout with the Banded Moray (Echidna polyzona). 

They have not been evaluated by the IUCN Red List of Endangered species.  

• Scientific Name: Gymnomuraena zebra
• Social Grouping: Varies – These eels are found alone in the wild, however they can also be found sharing a hideout with the Banded Moray (Echidna polyzona).
• IUCN Red List: NE – Not Evaluated or not listed – They have not been evaluated by the IUCN Red List of Endangered species.

Description

Zebra Moray Eels are orangish brown to dark brown over all with thin, vertical, white to pale yellow bars that may encircle the girth of the body, and are present from nose to tail.  Younger eels ones will have white vertical dashes spotting near the face and head, which will join to form full bands as they grow older.  Juveniles are less muscular and smaller around, but have similar markings as adults and grow very quickly, reaching maturity at 1.5 to 3 feet (57.2 to 102.7 cm).  The Zebra Moray have one continuous dorsal fin and a lower continuous pelvic fin.  Zebra Morays have 132 to 137 vertebrae, and due to the lack of scales, they produce a mucus layer over their for protection.  They also lack bone on their gill plates so they can squeeze into smaller crevices in the reef, as they search for food.  The Zebra Moray have pebble like teeth that are set close together, and are set in 2 to 3 rows in the upper and lower jaw; as well as 5 to 6 rows on the roof of their mouth.  These rows of teeth are angled back toward the throat, preventing the victim from escaping and helps them to swallow.  They have a rounded nose and poor eyesight, however, their excellent sense of smell, with 2 tube like appendages on their nose and two holes at the top of their head helps them locate prey.  It is said they can grow to 4.9 feet (1.5 m).  These fish can live up to several decades, so there is a huge commitment on the part of the aquarist. 

• Size of fish – inches: 60.0 inches (152.40 cm) – 4.9 feet (1.5 m) They reach full maturity at 1.5 to 3 feet (roughly 57 to 102 cm)
• Lifespan: 20 years – Zebra Moray eels can live 20 years or more.


Fish Keeping Difficulty

The Zebra moray will reach an eventual size of almost 5 feet, the Zebra Moray Eel will do better in a tank that is at least 250 gallons (1,000 liters).  This is based on the 50 gallons per foot of eel equation, which is a more accurate measure of what they need.  In a smaller tank, such as 75 gallons, poorer water quality results in diseases and depressed pH which can cause death.  Their body’s are so large and cumbersome, they will bump in to equipment and topple most structures in small tanks.  Besides, a 75 gallon tank is only 4 feet long and the Zebra Moray grows to almost 5 feet.  Larger tanks provide better water quality and room.  Although these eels are not as prone to try and escape, their curiosity can get the best of them, so a tank with a weighted lid is best.  Cleaning the tank every other week is suggested, unless the tank is 400 gallons or more, and done a day or two after feeding.  A very strong skimmer and strong water movement will also help with water quality, along with canister filters (only if you clean them weekly) in a fish only system.   Do not house with aggressive fish that pick on eels or may eat juvenile eel.  No fiberglass decorations are to be used, since they will cause the eel to develop sores on their skin.  Feed a wide variety of crustacean flesh, scallops, shrimp, etc., as well as occasional live crabs from saltwater sources.    

• Aquarium Hardiness: Moderately hardy
• Aquarist Experience Level: Intermediate – This is due to long term care and the need for a much larger tank, which is not common for beginners.

Foods and Feeding

The Zebra Moray Eel is a carnivore that should not be fed freshwater fish, flake or pellets.  To elicit a feeding response, try live foods such as small blue crabs, small shrimp and fiddler crabs.  You can easily train your eel during this time with chunks of crustacean flesh skewered on a feeding stick.  Gently bump the food on the nose and mouth of the eel once or twice, but if the eel does not take it try again the next day with a different food.   The foods that you need are easily found at your local grocery store!  These are fresh gulf shrimp with shells, cracked whole blue crab, scallops, and similar crustaceans and mollusks that are fully thawed.   Shrimp is fine, but should not be the majority of their diet, especially krill, which can be given as a treat once in a while.  Keep their food varied and feed adults once per week to satiation.  Since they are not fish eaters, they won’ go after your fish if you forget to feed them!  Do not over feed, or your eel can develop fatty deposits on it’s liver, compromising it’s health.  

• Diet Type: Carnivore – Must have a varied died of gulf shrimp with shells, cracked whole blue crab, scallops, squid and other crustaceans and mollusks from marine sources.
• Flake Food: No – They need fresh and varied crustacean and mollusk flesh.
• Tablet / Pellet: No – They need fresh and varied crustacean and mollusk flesh.
• Live foods (fishes, shrimps, worms): Some of Diet – Fiddler crabs and crayfish can be used to elicit a feeding response.
• Meaty Food: All of Diet
• Feeding Frequency: Weekly – Once per week as adults, more often as juveniles.

Aquarium Care

Reef tanks

Medium sized up to 90 gallons, perform 15 to 20% weekly. 

Large Tanks 100 gallons and over, once water is aged and stable can be changed 15% to 20% weekly, depending on bioload.

Fish only tanks:

Medium sized up to 90 gallons, perform 10% to 20% weekly. 

Large Tanks 100 gallons and over, 10 to 20% weekly.

For more information on maintaining a saltwater aquarium see: Saltwater Aquarium Basics: Maintenance. A reef tank will require specialized filtration and lighting equipment. Learn more about reef keeping see: Mini Reef Aquarium Basics.

• Water Changes: Bi-weekly – Perform a day or two after feeding them.

Aquarium Setup

Out of all the moray eels, the Zebra Moray is probably the most clumsy, so the rock work is in serious need of being very secure and heavy.  Provide several caves and hiding places around the tank, large enough to let them hide their entire body.   Providing multiple hiding places will help the Zebra Moray become calmer and it will feel safer, so it will eventually spend more time out in the open.  The area inside these hideouts should be completely dark.  PVC that is 3 to 4” around and 3 to 5 feet long can be used, but do not use decorations made out of fiberglass since it will cause sores on their bodies.  Although Zebra Morays are not prone to carpet surf like other eels, they still need a lid to prevent accidental “exploring!”   Sand is the best substrate since they like to burrow.  Juveniles under 2 feet can be temporarily housed in smaller tanks that are around 75 gallons, but they will outgrow that tank with in a short time.  Zebra Morays can be housed together if added at the same time in a tank that is twice as big for one, and lots of hideouts are provided.  

• Minimum Tank Size: 250 gal (946 L) – 250 gallons (1,000 liters) Older literature says 75 gallons, however use the calculations of 50 gallons per foot of eel.
• Suitable for Nano Tank: No
• Live Rock Requirement: Typical Plus Hiding Places – Multiple caves, castles and/or deep crevices large enough to hide their entire body

• Substrate Type: Sand – Sand would be better since they like to dig.
• Lighting Needs: Any – Ensure their hide out is completely dark inside.
• Temperature: 72.0 to 82.0° F (22.2 to 27.8&deg C) – 72˚ F (22˚ C) Cooler water will result in the eel refusing to eat. 82˚ F (28˚ C)
• Specific gravity: 1.023-1.025 SG – Keeping salinity near ocean levels will help keep the pH up.
• Range ph: 8.0-8.4 – Low pH will cause the eel to change in behavior and coloring.
• Brackish: No
• Water Movement: Strong – To aid in filtration
• Water Region: Bottom

Social Behaviors

The Zebra Moray is the most docile moray seen in aquaria, so far.  Two can be housed together if they are added at the same tim.  The tank should be very large, almost double, and there should be several hideouts per eel to help them feel secure.

Zebra Moray Eels can be housed with other pebble tooth eels, or morays that are less aggressive.  When it comes to fish friends, since they are strictly crustacean eaters, they leave even the smallest fish alone!  Their only downside is their huge adult size, but even then, they still make a great addition to a peaceful to semi-aggressive community tank!  Do not house with full grown, large adult groupers, soapfish or fish eating eels while the Zebra Moray Eel is still a juvenile, since they may be eaten.  

Corals are left alone, and the movements of the eel behind the rocks can help stir dead zones.  They can be kept in very very large reef systems over 500 gallons, if there are corals near the top and if the rock structure is very heavy and immovable.  When they are more comfortable, they will come out more often, and can rub against and break more delicate corals like birds nest corals.  Softies would be less affected unless the eel knocks them off their perch.  So the only time a durable coral is at risk is if the eel knocks it over or dislodges the rock the coral is affixed to.  This can easily be remedied by securing the rock and the coral.  SPS corals need much cleaner water than soft corals and some LPS. 

The inverts these eels are a threat to are crabs and other crustaceans and mollusks.  So snails, urchins, cowries and any crab will be eaten.  If a cleaner shrimp is added first, they may not eat them.  Starfish are usually safe.  

• Venomous: No
• Temperament: Peaceful – Peaceful towards other eels, fish and corals only.
• Compatible with:
  • Same species – conspecifics: Yes – In tank that is at least 500 gallons, add simultaneously, and provide lots of hideouts.
  • Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Safe
  • Semi-Aggressive (anthias, clownfish, dwarf angels): Safe
  • Safe
  • Large Semi-Aggressive (tangs, large angels, large wrasses): Safe
  • Large Aggressive, Predatory (lionfish, groupers, soapfish): Monitor – Do not house juvenile Zebra Moray Eels with full grown large adult grouper, soapfish or fish eating eels.
  • Safe
  • Anemones: Safe – Only if water quality is kept up and proper lighting is provided.
  • Mushroom Anemones – Corallimorphs: Safe – Only if water quality is kept up and proper lighting is provided.
  • LPS corals: Safe – Only if water quality is kept up and proper lighting is provided. Keep coral at upper levels to avoid being irritated.
  • SPS corals: Monitor – Avoid delicate species like birdsnest, digitata or other easily broken SPS. Keep up water quality and provide proper lighting. Keep coral at upper levels to avoid being irritated.
  • Gorgonians, Sea Fans: Threat – These are too delicate to withstand the Zebra Moray’s movements
  • Leather Corals: Safe – Only if water quality is kept up and proper lighting is provided.
  • Soft Corals (xenias, tree corals): Safe – Only if water quality is kept up and proper lighting is provided.
  • Star Polyps, Organ Pipe Coral: Safe – Only if water quality is kept up and proper lighting is provided.
  • Zoanthids – Button Polyps, Sea Mats: Safe – Only if water quality is kept up and proper lighting is provided.
  • Sponges, Tunicates: Safe – Only if water quality is kept up and proper lighting is provided.
  • Shrimps, Crabs, Snails: Monitor – Cleaner Shrimp are safe if added before the eel, however crabs, sea urchins and snails will be eaten.
  • Starfish: Safe
  • Feather Dusters, Bristle Worms, Flatworms: Safe
  • Clams, Scallops, Oysters: Monitor – May be knocked over by the eel.
  • Copepods, Amphipods, Mini Brittle Stars: Safe

Sex: Sexual differences

Unknown

Breeding / Reproduction

The Zebra Moray Eel is thought to be a protogynous hermaphrodite, meaning they begin life as a female and can change to males as needed.  Zebra Moray Eels are known to spawn in the summer, when the water is warmest.  The male and female will open their jaws very wide to signal the beginning of the courtship.  Their bodies will entwine and they will stay wrapped for several hours.  That is some serious “cuddle time!”  The female will then lay her eggs and the male then fertilizes them, and then they go their separate ways as the fertilized eggs float away.   The eggs are 1.8 to 4 mm and the larvae are called leptocephalus.  They are about 3” (7.62 cm), with small heads, large eyes and long, flattened, ribbon-like, clear bodies.  These little Zebra Moray babies spend 8 months floating near the surface in the open waters of the ocean.  Once they have matured to the point that they can defend themselves, they then settle into the reef and join the rest of that beautiful underwater world!
 

Not accomplished in captivity. See Breeding Marine Fish page for a description of how they reproduce in the wild.

• Ease of Breeding: Unknown

Fish Diseases

Occasionally, like all morays, your Zebra Moray eel may refuse to eat.  This can be caused by overfeeding, poor water conditions or a drop in water temperature.  Sometimes there seems to be no reason for an eel to go 2 weeks without eating, then it suddenly eats again.  If poor water conditions are suspected, it may take several weeks for them to start feeding again.  In the meantime, do several larger partial water changes to remedy the problem.  Morays have been known to go 2 months without eating, with not weight loss or health issues. 

Rarely, if ever are moray eels are inflicted by parasites.  Their behavior of flicking their dorsal fin up and down, head-shaking or rubbing it’s head against rocks or other hard, rough surfaces is a sign something is wrong.  Occasionally, eels contract nematode worms, which are squiggly, raised bumps under their skin.  Do not use medications containing copper compounds and oganophosphates, namely, masoten, dylox, Dipterex, Neguvon, and Malathion.  Malathion, for example is found in some medications to treat nematodes on fish.   What to do?  Massive water changes or place them in a treatment tank with PVC so they can hide, with an extremely heavy lid, and treat with erythromyin (Maracyn) for bacterial infections. 

Availability

Zebra Eels are easy to find online and your local fish store will order them for you.  They are more expensive than other eels because of their docile fish safe nature.

References

Animal-World Refernces: Marine and Reef

REEFKEEPING: An online magazine for the marine aquarist
A Serpent For Your Reef Tank: A Look at Fish-Safe Eels
By Frank Marini, PhD.
Reefkeeping Magazine™ Reef Central, LLC-Copyright © 2008 All rights reservedSHEDD The World’s Aquarium

AQUATIC COMMUNITY
Zebra Moray Eel – Gymnomuraena zebra
By Cacoa_Pleco
© 2004-8 Aquaticcommunity.com

 Zebra Moray (Gymnomuraena zebra) (Image Credit: George Berninger Jr., Wikimedia Commons CC BY-SA 4.0 International)