Tuxedo Urchin (Mespilia Globulus)

General Information 

The Tuxedo urchin (Mespilia globulus) is a well-known, beautiful, and reef-safe species of sea urchin. Due to its calm demeanor, this species is a much better alternative to sea urchins with long spines and pencil urchins.

The Tuxedo urchin is low-maintenance and serves as part of the tank cleaning crew – often roaming around, consuming algae sheets and debris it encounters.

This species is also friendly towards corals, so you can easily introduce it into your soft coral, LPS, or SPS saltwater aquarium without major concerns.

The Tuxedo urchin, Mespilia sp., is a species of sea urchin from the family Temnopleuridae.

There are approximately 1000 species of sea urchins worldwide. They belong to the same group as sea cucumbers, sand dollars, sea lilies, sea biscuits, and starfish.

The Tuxedo urchin (Mespilia globulus) is found naturally in tropical waters of the Indo-Pacific region across the entire Indian Ocean and western Atlantic Ocean, from Indonesia, the Philippines, to southern Japan.

These urchins inhabit shallow waters of coral reefs, seagrass beds, and coral rubble, at depths of up to 60 meters.

Similar to most sea urchins, the Tuxedo urchin is a benthic species with a spherical shape adorned with colorful bands and short, approximately 6-millimeter movable spines.

These spines are quite flexible and serve for movement, as well as passive defense. They are not toxic.

This species of urchin is quite attractive and decorative, characterized by wide, velvety, dark blue, or black bands between rows of short, brown, or tan spines.

Note: There is also an attractive reddish variety (Mespilia cf globulus) with blue or black bands and red spines.

The skeleton of the urchin consists of calcareous plates, forming a round and rigid structure. The mouth opening is located at the bottom of the animal.

Tuxedo urchins are relatively small – their diameter is approximately 7-8 cm when fully grown. In aquarium conditions, they typically measure around 5 cm.

There is no specific data available on the maximum lifespan of Tuxedo urchins in their natural environment. In captivity, their lifespan depends on various factors such as shipping and transport stress, living conditions, and water quality. In a well-maintained aquarium, Tuxedo urchins can live up to 3 years, although the average lifespan is around 1-2 years.

The Tuxedo urchin is undoubtedly a peaceful species and reef-friendly. Despite having numerous spines, this urchin does not display aggression towards other aquarium inhabitants.

These animals feed at night. During the day, they are less active and often lie simply on the surface of rocks or in crevices. At night, they emerge from their stronghold to feed on algae in the aquarium.

Tuxedo urchins are algae eaters; they consume troublesome algae, such as hair algae. Other food sources include filamentous microalgae, corals, and dried seaweed. They are often seen traversing the walls and equipment of the aquarium to clean them.

Aquarists should be prepared that Tuxedo urchins eat a lot and produce a lot of waste. They can “steal” various items they encounter, such as rocks, algae, coral fragments, snails, empty shells, and attach them to their bodies. They use them for camouflage from predators in the reef aquarium. If an individual is “naked,” it may indicate that the urchin is sick or stressed.

Feeding Tuxedo Urchin

A significant part of the Tuxedo urchin’s diet consists of algae, so it’s essential to have a mature aquarium with a constant supply of fresh filamentous algae.

In a reef aquarium, these urchins feed equally on debris and detritus as well as macroalgae species such as Chaetomorpha and Coralline. Keep this in mind if you’re one of the aquarists trying to support coral algae growth.

Note: Tuxedo urchins may even eat Caulerpa algae when hungry.

Although they are excellent scavengers and cleaning crew, make sure that this is not their sole source of food. If the aquarium does not provide a steady supply of algae for the Tuxedo urchin, it’s worth introducing supplemental feeding: dried seaweed sheets (nori), thin slices of carrots, spirulina.

Try to keep the supplemental food away from fish and other species in the aquarium; otherwise, they may eat it before the urchin gets to it.

A great way to minimize this is through spot feeding – hold the food right under the urchin until it reaches the top. Another option is evening feeding – the urchin will face less competition.

Tuxedo urchins are safe for reefs – they do not feed on corals, so there’s no need to worry about them picking at them.

Furthermore, studies have shown that the presence of urchins not only increased the survival rate of corals over 180 days but also accelerated the growth rate of corals! This is because microfeeding may play an essential role in increasing coral survival and growth.

Tuxedo urchins typically do not move or dislodge rocks from their normal position; other urchins do this. Nonetheless, it’s always recommended to attach corals to rocks.

Note: Tuxedo urchins may transport small and unattached Zoanthus or other polyps! In nature, zoas use this “transport” method to spread to other areas. Don’t worry; the urchins won’t puncture them with their spines.

Tank Size 

This species is well suited for various tanks, including nano tanks with a capacity of 40 liters. Because the Tuxedo urchin is small in size, it’s possible to keep it in such small aquariums.

However, smaller tanks may encounter feeding issues due to insufficient algae present in the aquarium.

Tuxedo urchins will thrive best in tanks of 60 liters or even larger.

Temperature: Tuxedo urchins are a tropical species; the ideal water temperature should be 22-26°C. Salinity: Maintain salinity levels between 1.021-1.025. Alkalinity: 8-11 dKH. pH: Keep the aquarium water pH within the range of 8.0-8.4.

Lights

These are nocturnal animals, so they don’t have specific lighting requirements. Lighting should be adjusted more to the needs of Chaetomorpha and Coralline algae.

Decorations and Hiding Places

Tuxedo urchins need a variety of small items to keep them happy, which they can “wear” on themselves. These could be empty shells, rocks, bits of rubble, etc. When these items become boring to the urchins, they simply detach them. When urchins can’t find suitable items to attach, they become stressed. A healthy urchin is typically covered with collected small items from the aquarium.

Sea Urchin Care and Breeding

Tuxedo urchins are low-maintenance candidates for a reef aquarium and as such are relatively easy to care for. They are also safe to handle (non-toxic).

As mentioned earlier, it’s important to ensure that the conditions in the reef aquarium are optimal and stable to keep the urchins healthy. It’s best to maintain moderate levels of lighting intensity and water flow; if the parameters are too high, they can harm the urchins.

Tuxedo urchins are quite sensitive to unfavorable water conditions, so try to maintain good water quality as often as possible. Poor water conditions and fluctuating parameters can sometimes cause the urchins to lose their spines.

Acclimatization

Before introducing a Tuxedo urchin into your tank, don’t forget about thorough acclimatization, as with all invertebrates. Do it very slowly (1-2 hours), allowing them to adjust to the new environment.

Common Tuxedo Sea Urchin Problems

Loss of spines: Urchins can lose their spines for several reasons, including elevated nitrate levels above 10 ppm, acclimatization shock, mishandling by fish, high stress levels, and poor water quality. The loss of spines makes them susceptible to bacterial infections, which can adversely affect their health and often doesn’t end well.

The priority is a slow, prolonged drip acclimatization of the Tuxedo urchin before transferring it to the display tank. During acclimatization, ensure that the water salinity matches that of the previous environment.

Also, strive to maintain stable parameters and cleanliness by regularly changing the water and providing sufficient food for the urchins.

Parasites: They feed on the soft tissues of Tuxedo urchins. If not removed, bald spots will appear on the urchins at first, and it will worsen over time, eventually leading to their death.

Solution: Manual removal. Personally, I don’t know of any chemical treatment that would be safe for the urchins.

Scratches: Urchins can also leave etching marks on acrylic tanks. Solution: Keep them in glass tanks.

Tuxedo Urchin Reproduction

Currently, the zoological industry is heavily reliant on wild-caught species. So far, there have been only a few reports of successful Tuxedo urchin breeding in reef aquariums.

If possible, opt for specimens bred in captivity rather than wild-caught ones. Captive-bred specimens are raised in controlled environments, making them better suited for aquarium life and more resistant to diseases.

Scant information in scientific literature indicates that:

This species undergoes sexual reproduction like most sea urchins. However, distinguishing between sexes requires a microscope. The male genital papilla protrudes from the body surface in the form of a short cone.

Tuxedo urchins reach full maturity at a diameter of 0.8-1 inch (2.0-2.5 cm). They are generally gonochoric and reproduce by releasing gametes (sperm and eggs) into the water. Females can release up to 270,000 oocytes (eggs).

Experimental results suggest that spawning occurs not only at the full moon but also at the new moon. Therefore, the same individual can spawn twice within a lunar month.

Fertilization occurs externally. The eggs are fertilized and float in the water for many months until hatching.

Prismatic larvae begin feeding on microalgae 3 days after fertilization. Embryos develop into planktotrophic larvae called echinoplateus and live for many months in the water column. However, under optimal conditions, metamorphosis occurs from the 21st day after fertilization.

They then settle on the bottom, using their tubular feet to attach to the substrate, where they undergo metamorphosis into young urchins. The average diameter of young Tuxedo urchins is about 1.53 mm 49 days after settlement.

Tuxedo Urchin is considered safe for the reef and can be kept with various marine fish and invertebrates.

You don’t have to worry about predation from aggressive fish, as the urchin uses its spines to deter them. However, parrotfish and triggerfish are exceptions, as they sometimes feast on urchins despite their spiny armor.

Summary 

Mespila globulus urchins are a fantastic addition to a reef aquarium. As they move around the tank, they collect various items. This species is safe for corals. They thrive on algae – if you can provide them with that, it’s worth having these urchins in your aquarium.