Tiny Reef Aquarium Invertebrates


Our aquariums are full of a huge variety of organisms that include exotic fish, stunning corals, and unusual invertebrates. Hobbyists tend to focus on the larger animals, after all we do pay for them, and the tiny creatures that roam our tanks are often overlooked. These animals can be nearly microscopic in many cases, usually hitch hike into an aquarium on live rock or coral frags, and can be both beneficial and detrimental to a reef aquarium depending on what they like to chew on. Fortunately, all of the organisms in the video above are those of the beneficial kind, or at the very least harmless to the aquarium livestock we purposefully put into the aquarium. Despite their beneficial nature, a lot of these invertebrates are widely misunderstood and most people fear them.

Below is a brief description of each of the inverts seen in the video above.

Dorvellid Bristleworm (Parougia sp.)
This bristleworm certainly looks menacing with its sharp mandibles and bristles covering its body. Fortunately, these worms are harmless, as the individual in the video above can obviously be seen grazing on the film algae that covers the glass. Dorvellid bristlworms are often extremely small, measuring only a few millimeters in length, and they usually go unnoticed in the typical aquarium. Very little information is known about this family of worms, but it appears to be a welcome hitch hiker.

Amphipod (Grammarus sp.)
Almost every aquarium keeper knows about Amphipods. These small crustaceans make up the staple diet of many fish and their presence is often an indicator of aquarium health. The bug-like amphipods are usually seen scurrying around the aquarium, often darting for a hiding place once the lights turn on. They are omnivorous, eating virtually anything they can get their claws on. Amphipods usually hitch hike into an aquarium in macroalgae and live rocks, but they can come in on frags and larger animals like clams.

Flatworm (Convolutriloba sp.)
The Convolutriloba flatworm, while virtually harmless, really represents more of an annoyance than anything else. Identifying these worms down to the species level is quite difficult, but the common theme surrounding this genus is their ability to rapidly multiply. If their numbers aren’t kept in check, either through manual removal or nutrient control, the flatworm population can absolutely explode. Much like our corals, the flatworms have symbiotic algae that lives in their tissue. Because of this, they get their nutrition primarily from photosynthesis, but they have also been known to eat algae and tiny crustaceans (depending on the species). The type seen in the video above is quite common, as I’ve seen them in multiple aquariums. They don’t seem to be as aggressive as their larger cousins, and from what I’ve seen, they don’t appear to stray too far from the aquarium’s glass.

Asterina Starfish (Asterina sp.)
Asterina starfish are just another hitch hiker that show up in marine aquariums. They eat a wide variety of things in the aquarium, and are usually found on the glass and rocks grazing on algae. Like other starfish, the Asterina expel their entire stomachs out of their mouths in order to digest food items and suck them back in. These starfish reproduce by fission, or splitting, which often leaves individuals with a lack of legs, which can look quite unusual.

Feather Duster Tube Worm
Aquarium-bound tube worms come in a huge variety, ranging from tiny hitch hikers to huge coco worms. The particular worm in the video above is just a tiny one, but full of bright colors. It came into the aquarium attached to the underside of a chalice frag, eventually growing out into the open where it could better filter food particles from the water. This worm, and a lot of those found in and out of the hobby, form a hard skeleton for protection. Other tube worms may use a soft sheath instead of the tube.

Spaghetti Worm
The spaghetti worms are a very unusual looking creature. They have a typical worm-like body, but their anterior portion is adorned with feeding tentacles. Depending on the species, these tentacles can be clear and limited to just a couple, or they can be yellow and numerous. Either way, the worms typically encountered in the home saltwater aquarium are harmless and feed on particles in the sand or floating by on the current. The worms can be quite unsightly and will reproduce quickly provided there is enough food to sustain a population. The yellow tentacled spaghetti worms are free-living and will either take up residence in the sand or rocks, but will also make snail shells their home (as seen in the video). The hard tube forming species typically live in the sand and glue grains of sand and rock onto their bodies to form a tube for protection. They often send out long feeding tentacles from this tube and drag in any captured food particles.

I also wanted thank Keith from Super Pet World for letting me film the spaghetti worms that abound in the store’s coral tanks.


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