Live Rock Hitchhikers and Species Identification Guide

The introduction of Live Rock is the single best way to increase the biodiversity of your aquarium. The goal is to try to obtain a balance and to match that which is found in nature. In the past, the word “hitchhiker” came with a negative connotation. We have come a long way in the hobby and the term hitchhiker is now used to describe the vast array of life of Live Rock hitchhikers. Nearly all of these creatures will add to the balance of life found in your tank.

The Beneficial Roles of Live Rock Hitchhikers:

  • Processing of waste and detritus.
  • Filtering your tanks water.
  • Stirring and oxygenating your sand-bed.
  • Keeping nuisance algae at bay.

99% of these hitchhikers are a valuable addition to your aquarium. This species identification guide will cover all these beneficial critters as well as the 1% that make up the bad hitchhikers and how to easily remove one should you be part of that 1% who get a hitchhiker that is not beneficial. This guide may help identify hitchhikers from other types of Live Rock but it is meant to be specific to ARC Reef Live Rock and ARC Reef Premium Live Rockboth of which are 100% Aquacultured Live Rock harvested from the Atlantic Ocean. If you have purchased our Live Rock and found a hitchhiker not listed feel free to Contact Us or call us at 1 (800) 268-ROCK and we’ll help you to identify that particular species of hitchhiker.

Coralline Algae (Red Algae Rhodophyta)

Coralline Algae is a type of red Algae in the order Corallinales. There are over 1600 known species with typically colors being purple, pink, and red but there are hundreds of different color variations, including blue, white, and green. It is a desirable algae to have in a saltwater aquarium and is an indication of a properly matured tank. Coralline Algae enters the system as one of the many beneficial “hitchhiker’s” on live rock. Coralline algae takes up real estate on live rock and out-competes other nuisance algae like hair algae, green algae, diatoms, and mat algae. Most coralline algae species are epiphytic and have chemical defenses to fight off other nuisance algae from growing on it. Check out some great looking examples of the vibrant color combinations on ARC Reef Live Rock and even more so on our Premium Live Rock.

Good Hitchhiker

Always Contains

Reticulated Brittle Star (Ophionereis reticulata)

Size: Fully matured adults will have arms up to 10″ in length. Juveniles are most common and can be as small as a dime. Light green to tan; pentagonal disc with thin dark reticulated lines; long arms with dark banding. Inhabits sand and reefs, often only extending arms from within live rock to feed. Very beneficial for marine aquariums, they help to remove detritus and uneaten food from aquarium.  Reef tank safe.  A very gentle species. Note: Brittle Stars will often come out of the rocks during shipping. It is important to do a careful inspection of the bottom of the bag and towel, place all living starfish into your tank. Sea Stars will regenerate lost limbs.

Good Hitchhiker

Very Common

Blunt-Spined Brittle Star (Ophiocoma echinata)

Size: Fully matured adults will have arms up to 6 in. in length. Long heavy blunt arm spines; tan, grey, brown, or black disk with tiny granules; occasionally white to tan petal pattern noticeable on disk. Inhabits sand and reefs, often only extending arms from within live rock to feed. Very beneficial for marine aquariums, they help to remove detritus and uneaten food from aquarium.  Reef tank safe.  Note: Brittle Stars will often come out of the rocks during shipping. It is important to do a careful inspection of the bottom of the bag and towel, place all living starfish into your tank. Sea Stars will regenerate lost limbs.

Good Hitchhiker

Common

Long-Spined Urchin (Diadema antillarum)

Size: spines are up to 8 in. long as adults. If found on live rock, almost always are juveniles. Numerous long thin, sharp spines. Exercise caution while handling; almost always black, occasionally white spines. Juveniles have spines that are black and white banded. Typically take shelter during the day and actively forage at night. Brittle needle like spines easily puncture skin and break off leaving dark discoloration beneath skin from dye in spines. Spines can be very difficult to remove but will dissolve within several days. Always treat with antiseptic initially, then use neosporen and dry bandage. Found from inter tidal zones down to 165 ft. Benificial for aquariums as they consume algae, but not recommended to have several at a time as they also consume coralline algae quicker than it can regrow.

Good Hitchhiker

Occasional

Variegated Urchin (Lytechinus variegatus)

Size: body to 4 in. Dense covering of short spines arranged in rows or clusters. Body is white; spines white, red, green, blue, brown, or purple. Spines are not sharp and would be difficult to puncture skin. It is common for them to collect several pieces of debris or shells and keep them on the topside of their body for camouflage. Beneficial for aquariums, but recommend only one per tank, they eat nuisance algae but can also eat coralline algae faster than it can grow back. Often found in sand or seagrass areas down to 160 ft.

Good Hitchhiker

Occasional

Slate-Pencil Urchin (Eucidaris tribuloides)

Size: body to 2 in. Thick blunt spines that resemble a navel mine; reddish white with reddish brown banding, often encrusted appearing gray. Secondary short spines are white to off white. Nocturnal; will stay inside rock-work during the day, and actively forage at night.  Beneficial to aquariums; will eat nuisance algae. Recommended one per tank so food is plentiful. Found on reefs down to 150 ft.

Good Hitchhiker

Occasional

Starlet Coral (Siderastrea radians)

Size: 4-12 in. Colonies usually form flat encrusting plates, but occasionally grow in small irregular rounded domes. Surface is covered with small, deep-pitted corallites that often appear pinched in. Usually whitish to tan, occasionally rose colored. Center or corallite appears darker in color. Inhabit rocky substrates and patch reefs from inter-tidal zones down to 35 ft. Hardy corals that can tolerate a variety of conditions including fluctuations in temperature, salinity, surge, and turbidity.

Good Hitchhiker

Common

Ghost Feather Duster (Anamobaea sp.)

Size: crown 3/4 in. Circular crown of radioles nearly colorless to white with three very faint maroon bands; darker ring just above mouth. Can be found in large clusters or independent. Parchmentlike tube visible. Very good motion detection; will retreat inside itself when motion is detected within several ft. Found in rock-work and sand beds on the outskirts of reefs from depths of 15 ft. down to 60 ft.

Good Hitchhiker

Very Common

Split-Crown Feather Duster (Anamobaea orstedii)

This ARC Reef Live Rock article is pending and will posted pending approval. Atlantic Reef Conservation is a federally and state licensed aquaculture facility striving to make a positive change for our natural reefs. All our products our 100% aquacultured. For every 1 lb. of Live Rock purchased, ARC Reef plants 10 lbs of new reef material offshore. To date we have created over 43,500 sq ft. of new coral reefs. We thank you in advance for choosing aquacultured products and we hope that our site is able to provide you with valuable information in regards to live rock, coral reef restoration, and general aquarium husbandry.

Good Hitchhiker

Very Common

Star Horseshoe Worm (Pomatostegus stellatus)

This ARC Reef Live Rock article is pending and will posted pending approval. Atlantic Reef Conservation is a federally and state licensed aquaculture facility striving to make a positive change for our natural reefs. All our products our 100% aquacultured. For every 1 lb. of Live Rock purchased, ARC Reef plants 10 lbs of new reef material offshore. To date we have created over 43,500 sq ft. of new coral reefs. We thank you in advance for choosing aquacultured products and we hope that our site is able to provide you with valuable information in regards to live rock, coral reef restoration, and general aquarium husbandry.

Good Hitchhiker

Very Common

Christmas Tree Worm (Spirobranchus giganteus)

This ARC Reef Live Rock article is pending and will posted pending approval. Atlantic Reef Conservation is a federally and state licensed aquaculture facility striving to make a positive change for our natural reefs. All our products our 100% aquacultured. For every 1 lb. of Live Rock purchased, ARC Reef plants 10 lbs of new reef material offshore. To date we have created over 43,500 sq ft. of new coral reefs. We thank you in advance for choosing aquacultured products and we hope that our site is able to provide you with valuable information in regards to live rock, coral reef restoration, and general aquarium husbandry.

Good Hitchhiker

Occasional

Spaghetti Worm (Eupolymnia crassicornis)

This ARC Reef Live Rock article is pending and will posted pending approval. Atlantic Reef Conservation is a federally and state licensed aquaculture facility striving to make a positive change for our natural reefs. All our products our 100% aquacultured. For every 1 lb. of Live Rock purchased, ARC Reef plants 10 lbs of new reef material offshore. To date we have created over 43,500 sq ft. of new coral reefs. We thank you in advance for choosing aquacultured products and we hope that our site is able to provide you with valuable information in regards to live rock, coral reef restoration, and general aquarium husbandry.

Good Hitchhiker

Very Common

Medusa Worm (Loimia medusa)

This ARC Reef Live Rock article is pending and will posted pending approval. Atlantic Reef Conservation is a federally and state licensed aquaculture facility striving to make a positive change for our natural reefs. All our products our 100% aquacultured. For every 1 lb. of Live Rock purchased, ARC Reef plants 10 lbs of new reef material offshore. To date we have created over 43,500 sq ft. of new coral reefs. We thank you in advance for choosing aquacultured products and we hope that our site is able to provide you with valuable information in regards to live rock, coral reef restoration, and general aquarium husbandry.

Good Hitchhiker

Occasional

Common Bristle Worm (Polychaete linopheris)

Size: to 8 in. Considered a beneficial hitchhiker. Is not a fireworm. The common Bristle worm is a detritivore, only eats detritus. Excellent at stirring the sand-bed and keeping your tank clean. Will not go after fish or corals.

Good Hitchhiker

Occasional

Bearded Fireworm (Hermodice carunculata)

Size: to 12 in. Fleshy beardlike appendage on head; short tufts of white bristles and red gill filaments line body; red, green, yellow, or brown. Juveniles brown. Inhabit multiple environments such as rock-work, sandbed, coral bases, holes, cracks, and crevices. Nocturnal. Found from inter-tidal zones down to 130 ft. Bristles cause painful wound and can remain stuck in skin, may require tweezers to remove. The Bearded Fireworm is a type of bristle worm. It is not an ambush predator, but is an opportunistic feeder. Can bite or irritate corals. Will claim a recently deceased fish, but are rarely the cause of the death. Smaller sized fireworms can coexist peacefully in an aquarium but should be watched. Removal is recommended if watching is not possible. For removal tips, species identification, and more information, click here to read all about Bristle Worms, Fireworms, & Polychaete.

Bad Hitchhiker

Very Rare

Corkscrew Anemone (Bartholomea annulata)

This ARC Reef Live Rock article is pending and will posted pending approval. Atlantic Reef Conservation is a federally and state licensed aquaculture facility striving to make a positive change for our natural reefs. All our products our 100% aquacultured. For every 1 lb. of Live Rock purchased, ARC Reef plants 10 lbs of new reef material offshore. To date we have created over 43,500 sq ft. of new coral reefs. We thank you in advance for choosing aquacultured products and we hope that our site is able to provide you with valuable information in regards to live rock, coral reef restoration, and general aquarium husbandry.

Neutral

Uncommon

Aiptasia Anemone (Aiptasia sp.)

Aiptasia anemones are commonly found in lagoons, inter-tidal areas, and shallow mangrove lined shorelines.  Our artificial reef is located in deeper water, far fro their natural habitat, so while it is very rare for ARC Reef Live Rock to ever have any aiptasia on it, it is not impossible, so we have included it in our hitchhikers guide. To date we have never witnessed one on our live rock and have not received a single report by anyone who has purchased our live rock. If you believe you have found an anemone on your live rock, it is more likely to be a corkscrew anemone. Aiptasia anemones reproduce extremely quickly. While they will not be any issue for the diligent reefer, they can reproduce like wildfire for the lazy reefer.  It is recommended to remove them as soon as you notice one. Removal is very easy. There are many removal techniques but we only recommend one method.  The Kallkwasser Paste Injection Method, which involved adding kallkwasser powder and a tablespoon of water, then using a syringe to inject this paste into the anemone.  Warning: do not try to manually remove, this may spawn additional anemones.

Bad Hitchhiker

Rare

Pistol Shrimp (Scientific name)

This ARC Reef Live Rock article is pending and will posted pending approval. Atlantic Reef Conservation is a federally and state licensed aquaculture facility striving to make a positive change for our natural reefs. All our products our 100% aquacultured. For every 1 lb. of Live Rock purchased, ARC Reef plants 10 lbs of new reef material offshore. To date we have created over 43,500 sq ft. of new coral reefs. We thank you in advance for choosing aquacultured products and we hope that our site is able to provide you with valuable information in regards to live rock, coral reef restoration, and general aquarium husbandry.

Good Hitchhiker

Occasional

Common Name (Scientific name)

This ARC Reef Live Rock article is pending and will posted pending approval. Atlantic Reef Conservation is a federally and state licensed aquaculture facility striving to make a positive change for our natural reefs. All our products our 100% aquacultured. For every 1 lb. of Live Rock purchased, ARC Reef plants 10 lbs of new reef material offshore. To date we have created over 43,500 sq ft. of new coral reefs. We thank you in advance for choosing aquacultured products and we hope that our site is able to provide you with valuable information in regards to live rock, coral reef restoration, and general aquarium husbandry.

Good Hitchhiker

Occasional

Common Name (Scientific name)

This ARC Reef Live Rock article is pending and will posted pending approval. Atlantic Reef Conservation is a federally and state licensed aquaculture facility striving to make a positive change for our natural reefs. All our products our 100% aquacultured. For every 1 lb. of Live Rock purchased, ARC Reef plants 10 lbs of new reef material offshore. To date we have created over 43,500 sq ft. of new coral reefs. We thank you in advance for choosing aquacultured products and we hope that our site is able to provide you with valuable information in regards to live rock, coral reef restoration, and general aquarium husbandry.

Good Hitchhiker

Occasional