The fascinating Snake Polyps may be ugly little buggers, but they “love the night life”!

   The Snake Polyps of the Isaurus genus with their gnarled, warty, tubular appearance, do command attention. They can be a single polyp or polyps connected with stolons. Their polyps have long tube-like bodies and very short tentacles. These long cylindrical bodies will have bumps on the sides and the end. Other common names they are known by are Tube Polyps, King Polyps, Stick Polyps, and Coral Bananas.

   At times they will face downward or sideways, or any which way they like. In the wild the Snake Polyps grow at the tops of reefs or on sediment, and are often partially buried in sediment. The small tentacles extend mostly at night to feed, yet their columns contain the marine algae, zooxanthellae, which helps to provide much of their nutrition. Their colors are generally gray, brown, or green.

   Though not as common in the aquarium trade as other zoanthid type corals, the Isaurus genus can be located a lot easier now than a few years ago. These zoas were first found as hitchhikers on rocks or other coral bases, but have slowly become more and more favored. Their popularity is just starting to grow, so grab some sweet green ones and bring out their color with actinic lighting.

   The Snake Polyps are not too hard to maintain. Like other zoanthids they need bright lighting, regular feeding, and good water flow. Even though they are scary looking, they are as peaceful as they come. They will actually need you to protect them by proper placement. They love to eat, but feed them after the lights go out at night when their tentacles are apparent. Though they are not always open during the day, they are still a fascinating attention getter.

Scientific name

   Family: Zoanthidae
   Species: Isaurus sp.

Distribution / Background

   Isaurus Coral Information: The Isaurus genus was described by Gray in 1828. The valid species found in the Atlantic are I. duchassaingi, and I. spongiosus; species found in the Pacific are I. cliftoni and I. maculatus; and one species, I. tuberculatus, is found in both oceans. Common names this species is known for are Tube Polyps, King Polyps, Stick Polyps, and Coral Bananas.

   Where Isaurus Corals Are Found: The Isaurus genus found in both the Atlantic and Pacific oceans.

   Isaurus Coral Habitat: The Isaurus genus are located on reef crests or on sediments, and have body columns that are usually partially buried in sediment. They like areas that are low in water flow, yet have a good amount of light.


   The Isaurus genus is not on the IUCN Red List for Endangered Species.


   What do Isaurus Corals look like: All the species in the Isaurus genus have similar appearances and needs. Snake Polyps have soft bodies covered with a leathery skin, called the cuticle, which gives them protection. They can be a single polyp or polyps connected with stolons. These polyps are long cylindrical in shape with bumps on the sides and the end, and they like to bury part of their column in sediment.

   They have very small tentacles at the tip that come out at night. The column can be tan, gray, brown or green, with tentacles that can be white or another light version of the main polyp. Similar to Palythoa and Protopalythoa, they do have zooxanthellae in their epidermis and gastrodemermis, meaning they will need light to survive.

Difficulty of Care

   Isaurus Coral Care: The Isaurus genus is moderate to care for as long as they have adequate bright lighting, regular feeding, and good water flow. Feed after lights out when their tentacles are apparent.

   They are a recommended aquarium coral, but with some caution. The Zoanthidae family produce palytoxin, one of the most potent poisons known to science. For this reason one should take care when handling them. Don’t handle them if you have cuts or open wounds and make sure to clean your hands after handling.

   There are a couple of cautionary items to be aware of when you keep Zoanthids:

  • Palytoxin
      The members of the Zoanthidae family have varying degrees of poison called palytoxin. All of the Palythoa genus and most Protopalythoa genus produce a high level of this poison in their mucus and gonads. Other genera, such as the Zoanthus genus, have it to a lesser extent, and so a less dangerous degree.
       To be affected by this toxin, it must either be ingested or must enter the bloodstream. It can enter the system through an open wound. It has been suggested by some that it may also be absorbed through skin contact though this is not confirmed.
       The danger to the aquarist is minimal with proper precautions. If you have a cut on your hand, this poison can get into your system, but in average aquarium keeping it is unlikely to pose any danger beyond a localized skin reaction. Some hobbyists wear gloves when handling these organisms.

    Here’s a couple interesting facts!
       Fish that eat Paly polyps, like the filefish, can bring this palytoxin in to the human food chain. This would be when a predator of the filefish is a fish that is typically eaten by humans.
       Also, Pacific tribes used to use this neuromuscular poison to paralyze enemies and prey animals by coating their spears with the mucus of these corals.

  • Vibrio Infection
       Vibrio can at times be in the coral mucus, thus causing a Vibrio infection in humans if care is not taken. Most people have no problem, but caution and common sense play a role here. Wearing gloves and possibly goggles may be the safe route to go. After handling a Zoanthid, make sure the mucus is not on your glove or hand before handling any other corals!

Foods / Feeding

   Isaurus Coral Feeding: In the wild, Isaurus corals have developed several feeding strategies. Through a symbiotic relationship with a marine algae, known as zooxanthellae, they receive the majority of their nutrients. They also capture planktonic organisms and microscopic food particles from the water column, and can absorb dissolved organic matter.

   In captivity it is necessary to provide bright lighting for the Snake Polyps, but the Isaurus genus does need supplementary feedings as well. Offer zooplankton, daphnia, Cyclopeeze, or brine shrimp on a weekly basis, or as needed to multiply quicker. This is as necessary as lighting.

   Snake Polyps feed at night when the lights are off. This is when they start showing their little tentacles that resemble small feathers, so be sure to target feed them at that time. It has been said that if food is present in the water during the day this may elicit a feeding response, so they may show their tentacles then as well.

Aquarium Care

   Stable tank conditions are needed to keep the Isaurus genus. Doing water changes of 20% a month or 10% biweekly is needed, although it is suggested that doing 5% water changes once a week will replenish many of the needed additives. Make sure iodine is present, and also the addition of trace elements may help with the Snake Polyps survival.

   Suggested levels for Isaurus species are:

  • Calcium:  380 – 430 ppm
  • Alkalinity:  3.2 – 4.8 MEQ/L (8 to 11 dKh – 10 is recommended)
  • Phosphates:  0, zero.
  • Magnesium:  1200 – 1300 ppm.
  • Strontium:  8 – 10

Aquarium Parameters

Quick Reference Chart
Lighting:Prefers Low Lighting LevelsPrefers Medium Lighting LevelsPrefers High Lighting Levels
Water Flow:Prefers Low Water Flow LevelsPrefers Medium Water Flow LevelsPrefers High Water Flow Levels
Temperament:Peaceful TemperamentSemi-Aggressive TemperamentAggressive Temperament

   A typical live rock/reef environment is what is needed for your Snake Polyps, along with some fish for organic matter production. A mature tank (well over a year old) is advised to increase the successful keeping of Isaurus.

   Provide proper lighting and water movement. Moderate water flow and a strong light source are required for Snake Polyps to do well. These are not an aggressive species. They get along well with their own kind, but space should be provided between them and other corals.

  • Minimum Tank Size / Length: 10 gallon Nano (38 L) or larger
  • Marine Lighting: Moderate to high
  • Temperature: 72° – 83° F (22° – 27° C)
  • Salinity / Specific Gravity: 1.023 – 1.025
  • Water Movement: Moderate
  • Water Region: Top of the aquarium for adequate lighting

Compatibility and Social Behaviors

   The Isaurus genus will get along with itself, but does need to be placed in an area where they will be protected from being grown over by other zoanthid species. They also need to be kept away from any coral that may sting them. As with most zoanthids, mushroom anemones should not be placed nearby.

   Snake Polyps are not an aggressive species. They can be kept in the company of small peaceful coral reef fish and shrimp, and hermit crabs. Other good tank mates include small tangs and blennies that will feed on filamentous algae. Avoid large crustaceans, large angelfish, and most butterflyfish. Sea Anemones and Tube Anemones should also be avoided.

Sex – Sexual differences

   No sexual difference in appearance is known.

Breeding and Reproduction

   The Isaurus genus reproduce by forming and budding off new polyps, when given desirable living arrangements.

   Propagation is rather simple for Isaurus corals, simply cut the mat or chip away under the polyp’s grip. They can be out of the water a few minutes with no ill effects. Dry the bottom of the mat or debris that the polyp is stuck to, and the rock or plug you will be putting it on. Then use super glue (the gel is the best) to connect them. Wait a few seconds for it to set and then put the new frag back into the water.

Potential Problems

  The Isaurus genus is generally hardy and durable if provided with a proper reef environment. However be cautious of filamentous algae as it will overgrow and smother polyps.

   A snail called the Box Snail or Sundial Snail Heliacus areola preys on Zoanthid colonies, so must be removed if seen. Avoid large crustaceans and aufwachs feeders, such as large angelfish and most butterflyfish, that like to nibble on their tentacles.


   Isaurus Corals for Sale: The Snake Polyps or Tube Polyps Isaurus sp. are very easy to find at pet shops and on line. Online they can run about $24.00 to $44.00 USD or more, depending on the size. You can also occasionally buy them in smaller amounts for around $5.00.


Isaurus tuberculatus rétracté (Image Credit: Philippe Bourjon, Wikimedia Commons CC BY-SA 4.0 International)