This is a list of various species of marine invertebrates, animals without a backbone, that are commonly found in aquariums kept by hobby aquarists. Some species are intentionally collected for their desirable aesthetic characteristics. Others are kept to serve a functional role such as consuming algae in the aquarium. Some species are present only incidentally or are pest species.
Annelids Common name(s) Image Taxonomy Reef safe Care Level Description Max size Christmas tree worm Spirobranchus giganteus Yes Expert Found living anchored in live coral colonies in nature. Each worm has two crowns, which come in a variety of different colors, and are spiraled in the shape of a Christmas tree. Cluster duster Bispira brunnea Yes Moderate This species grows in groups of up to 100 individual tube worms, living together in a single clump. The clusters of tubes adhere to a rocky substrate at a central point. Feather duster worm, Fan worm Sabellastarte sp. Yes Easy to Moderate A sedentary (but it can scoot around), tube dwelling worm with a fan-shaped crown (radiole) that projects from the end of the tube. This can be white, tan, orange, sometimes with striping. They build their tubes out of sand, mud, and bits of shell.
Arthropods
Chelicerates Common name Image Taxonomy Reef safe Care Level Description Max size Atlantic horseshoe crab Limulus polyphemus Yes, with caution Easy A bottom dwelling animal that is actually not a true crab. Found burrowing in mud or sand flats in the wild, they need a deep sand bed in their aquarium. Sea spider Pycnogonids No Moderate Not collected for the aquarium trade, but occasionally seen on live rock and corals as a hitchhiker. They can be pests in a reef tank, preying on soft coral, sponges and anemones.
Crustaceans Common name Image Taxonomy Reef safe Care Level Notes Max size Anemone crab Neopetrolisthes maculatus Yes Easy It lives in anemones. Also a filter feeder Arrow crab Stenorhynchus seticornis with caution Hermit crabs Paguroidea sp. Will eat snails Easy Emerald crab Mithraculus sculptus With caution? Easy May eat fish Pom-pom crab Lybia tessellata With caution? Easy? Sally lightfoot crab Percnon gibbesi With caution? Easy? Spider decorator crab Camposcia retusa With caution? Easy? Will get some polyps to use for cover. Spiny lobster Panulirus versicolor Brine shrimp Artemia salina Yes Easy Kept not as livestock, but rather to feed inverts and fish. Sexy shrimp Thor amboinensis Yes Easy Snapping shrimp Alpheidae sp. With caution? Will make loud snapping sounds. Peacock mantis shrimp Odontodactylus scyllarus with caution Easy Will eat shelled things and possibly fish. Some people say they will redecorate their tank including moving corals but people have successfully kept them in reef tanks. Not a true shrimp but a stomatapod with the smashing raptorial appendage Coral banded shrimp Stenopus hispidus Yes Easy Will eat small fish, in the wild they set up cleaning stations Camel shrimp Rhynchocinetes durbanensis Yes Easy? Will nip on soft corals. Harlequin shrimp Hymenocera sp. Will eat starfish Moderate? Will only eat starfish. Peppermint shrimp Lysmata wurdemanni complex Yes Easy Some people think they eat corals, but they only eat dying coral (although this gives the appearance of eating healthy corals) Skunk cleaner shrimp Lysmata amboinensis Yes Easy Will clean dead tissue and remove parasites from fish.
Corals
Corallimorphs Common name(s) Image Taxonomy Temperament Care Level Description Max size Jewel anemone Corynactis viridis small polyps with all colours 1 cm Knobbly mushroom coral, Florida false coral Ricordea florida a knobbly coral with vibrant colours 7 cmKnobbly mushroom coral, Yuma mushroom coral Ricordea yuma Semi-aggressive Moderate 1 meter Mushroom coral, Mushroom anemone, Disk anemone Discosoma sp. Semi-aggressive Easy 50 cm Strawberry anemone Corynactis californica small red polyps with pink tentacles 2.5 cm
Hydrocorals Common name Image Taxonomy Temperament Care Level Description Max size Lace coral Distichopora sp. Fire coral Millepora sp.
Large-polyp stony Common name(s) Image Taxonomy Temperament Care Level Description Max size Black sun coral Tubastraea micrantha Expert Bubble coral Plerogyra sinuosa Aggressive Easy Candy cane coral Caulastrea furcata Peaceful Easy Elegance coral Catalaphyllia jardinei Aggressive Moderate Flowerpot coral Goniopora sp. Aggressive Difficult Frogspawn coral Euphyllia divisa Aggressive Moderate Hammer coral, Anchor coral Euphyllia ancora Aggressive Lobed brain coral Lobophyllia hemprichii Semi-Aggressive Open brain coral Trachyphyllia geoffroyi Semi-aggressive Pineapple brain coral, Moon coral Favia sp. Aggressive Sun coral, Orange cup coral Tubastraea sp., often Tubastrea aurea Peaceful Expert Torch coral Euphyllia glabrescens Aggressive Whisker coral, Duncan coral Duncanopsammia axifuga Peaceful Easy
Small-polyp stony Common name Image Taxonomy Temperament Care level Description Max size Pink bird's nest coral Seriatopora hystrix Cauliflower coral Pocillopora sp., usually Pocillopora damicornis Dimpled encrusting Montipora Montipora verrucosa Finger coral Montipora digitata and Montipora samarensis Millepora coral, "Milli" coral Acropora millepora Peaceful Moderate A popular and readily available species that comes in many color forms. It should not be confused with fire corals of the genus Millepora. Plating montipora Montipora capricornis Peaceful Moderate Staghorn coral Acropora cervicornis Peaceful Difficult A very rare species, it is generally not available to the average hobby aquarist due to its critically endangered status. They would likely make good aquarium specimens, but can only be obtained with a special license.
Soft corals Common name(s) Image Taxonomy Temperament Care Level Description Max size Cabbage leather coral Sinularia brassica and Sinularia dura Semi-aggressive Easy Clove polyps, Daisy polyps Clavularia sp Peaceful Easy Devil's hand leather coral Lobophytum sp. Peaceful to Semi-aggressive Easy Finger leather coral Sinularia sp. Semi-aggressive Easy Jasmine polyps, Daisy polyps Knopia Peaceful Easy Pulse coral, Pulsing Xenia Xenia sp. Peaceful Easy An easy to care for coral known for its prolific asexual reproduction and polyps that actively move their tentacles in a pulsing motion. Red chili coral Nephthyigorgia Peaceful Expert Spaghetti leather coral Sinularia flexibilis Semi-aggressive Easy Star polyps Clavularia viridis, Pachiclavularia viridis, or Briareum violaceum (taxonomy uncertain) Peaceful Easy
Zoanthids Common name(s) Image Taxonomy Temperament Care Level Description Max size Stick polyps, Tree polyps Acrozoanthus Button polyps, Zoanthids, "Zoas" Zoanthus Semi-aggressive Easy Common, but pretty, coral that is a mainstay of the reef hobby. Their diversity of color is almost infinite, ranging from pale to full-on rainbow. Button polyps, Palythoa, "Palys" Palythoa Semi-aggressive Easy Palythoa are nearly as ubiquitous as Zoanthus in the reef hobby. Their colors are usually more muted, but still attractive. Button polyps, Protopalythoa Protopalythoa Semi-aggressive Easy Similar to Palythoa, these may actually be in the same genus due to taxonomic uncertainty.
Echinoderms
Sea cucumbers Common name Image Taxonomy Reef safe Care Level Description Max size Florida sea cucumber Holothuria floridana Pink and black sea cucumber Holothuria edulis Yes Easy Sea apple Pseudocolochirus axiologus Maybe Expert Tiger tail sea cucumber Holothuria hilla Yellow sea cucumber Colochirus robustus With care Expert
Starfish Common name(s) Image Taxonomy Reef safe Care Level Description Max sizeBlue and pink sea star Astropecten sp. Brittle star Ophiomastix Yes Easy Bun star Culcita novaeguineae With care? Chocolate chip sea star Protoreaster nodosus No Moderate? Blue linckia Linckia laevigata Indian Sea Star Fromia indica Yes Moderate Mottled linckia Linckia multifora Little red star Fromia elegans Purple linckia Linckia teres, or Tamaria stria Yes Difficult Red Sea Star Fromia millepora Yes Moderate Red-knobbed starfish Protoreaster linckii No Sand sifting sea star Astropecten polyacanthus Yes Easy Needs a large sandbed Tiled sea star, marbled sea star Fromia monilis Yes Moderate
Crinoids Common name Image Taxonomy Reef safe Care Level Description Max size Feather star Himerometra robustipinna Yes Expert One of the most difficult species to keep alive in a home aquarium
Urchins Common name(s) Image Taxonomy Reef safe Care Level Description Max size Black longspine urchin Diadema setosum Collector urchin, Priest hat urchin, Sea Egg Tripneustes gratilla Globe urchin, Tuxedo urchin Mespilia globulus Yes Easy Very common in the aquarium trade Slate pencil urchin Eucidaris tribuloides Purple short spine pincushion urchin Pseudoboletia maculata Red slate pencil urchin Heterocentrotus mamillatus Reef urchin, Rock boring urchin Echinometra sp. Variegated urchin Lytechinus variegatus
Jellyfish Common name Image Taxonomy Reef safe Care Level Description Max size (bell diameter)Blue Blubber Jellyfish Catostylus mosaicus No Expert This jellyfish actually ranges in color from white to dark purple to reddish brown. It has a dome-shaped bell which pulses at a quick, steady pace, making these jellyfish strong, active swimmers. Moon jellyfish Aurelia aurita No Moderate to Difficult A whitish to clear jellyfish with a large dinner-plate shaped bell. They have a fringe of short tentacles around the edge of the bell, and four longer oral arms extending from around the mouth. Sea Nettles Chrysaora sp. No Expert Range in color from white to striped orange and brown to purplish. Long tentacles trail behind the bell, sometimes for several meters. Upside Down jellyfish Cassiopea sp. No Expert This jellyfish has a somewhat green or grayish blue coloration due to symbiotic algae living in its tissues. It resides on the bottom, exposing its tentacles (and the algae inside them) to the light. very similar to coral in behavior
Mollusks
Bivalves Common name Image Taxonomy Reef safe Care Level Description Max sizeAtlantic Thorny oyster Spondylus americanus Bear paw clam Hippopus hippopus Blue clam, Boring clam Tridacna crocea Yes China clam Hippopus porcellanus Electric flame scallop Ctenoides ales Yes Flame scallop Ctenoides scaber Yes Fluted giant clam Tridacna squamosa Yes Moderate? Flying scallop Promantellum vigens Gigas aka "Giant" clam Tridacna gigas Yes Maxima clam Tridacna maxima Yes Moderate Southern giant clam Tridacna derasa Yes Thorny oyster Spondylus sp.
Gastropods Common name Image Taxonomy Reef safe Care Level Description Max sizeAbalone Haliotis sp. Yes Easy Arabian Cowrie Cypraea arabica Astraea snail Astraea sp. Yes Easy Bumble bee snail Engina mendicaria Yes Easy Cerith snail Cerithium sp. Yes Easy Gold ring cowrie Cypraea annulus Lettuce sea slug Elysia sp., usually Elysia crispata Yes Moderate A sacoglossan sea slug with folded parapodia (side appendages), that give it a lettuce-like appearance. They feed on algae, and incorporate algal chloroplasts into their cells. Color ranges from brownish to green, and can include blues, yellows, and pinks. Nassarius snail Nassarius sp. Yes Easy Queen conch Eustrombus gigas Yes, but may knock over loose rocks and coral. Sand conch Strombidae Yes Easy Sea Hare Aplysiomorpha sp., usually Aplysia sp. or Dolabella sp. Yes Expert Tiger cowrie, Cypraea tigris Trochus snail Trochus sp. Yes Easy Turbo snail Turbo sp. Yes Easy
Cephalopods Common name Image Taxonomy Reef safe Care Level Description Max sizeCommon tropical octopus Octopus vulgaris No Expert Mantle: Arms: Dwarf cuttlefish Sepia bandensis No Expert Mantle: European common cuttlefish Sepia officinalis No Expert Mantle:
Sea anemones