Orange Marble Sea Star

Quick facts

Identity

Also known as

Necklace Starfish; Marble Starfish; Tile Sea Star

Synonyms

Fromia monilis

Environment

Saltwater

Native to

Indo-Pacific, Red Sea, East Africa, Madagascar, Philippines, Australia, Vanuatu

Habitat

Shallow coral reefs, lagoons, and outer reef slopes to about 40 m, on live rock rich in biofilm and microalgae

Sourcing

Wild-caught

Conservation

Not Evaluated

Care

Care level

Difficult

Temperament

Peaceful

Adult size

2 – 5 in (5.1 – 13 cm)

Lifespan

4 – 7 yrs

Min tank

40 gal (151 L)

Growth rate

Slow

Placement

Bottom, Rock & glass

Water

Temperature

74 – 80 °F (23 – 27 °C)

pH

8.1 – 8.4

dKH

8 – 12 dKH

Salinity

1.023 – 1.025 SG

Flow

Low-Moderate

Behavior & compatibility

Social

Solitary

Aggression to own kind

Low

Active

Daytime

Reef safe

Yes

Invert safe

Yes

Shrimp safe

Yes

Clean-up role

Algae, Biofilm, Detritus

Population boom risk

Low

Feeding & breeding

Diet

Detritivore

Foods

Frozen, Biofilm, Algae

Breeding type

Broadcast spawner

Breeding difficulty

Not bred in captivity

Sexing

Sexes are not visually distinguishable

Target feeding

Beneficial

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Care guide

Overview

Grazes slowly across live rock and sand, picking biofilm and detritus from crevices with white marbling patterned over an orange to burnt-orange body. Regrowth of lost arms is possible over time. Only suited to established reef systems with months of run time, stable parameters, and no copper-based treatments.

Care

This sea star needs a mature, well-established reef system with several months to a year of run time so it can graze on the biofilms, microalgae, and detritus that accumulate on live rock. It is sedentary and moves little from day to day, so a lack of movement is not unusual, but complete inactivity paired with discolored patches or a soft, deflating body signals real trouble. Copper-based medications are lethal to it and must never be dosed in a tank housing this animal, and water parameters should stay very stable, since sudden shifts in salinity, pH, or temperature are poorly tolerated. A deep sand bed and plenty of open rockwork give it room to forage.

Feeding

In the wild and in a mature aquarium, this species grazes bacterial films, organic detritus, sponges, and microalgae off live rock and substrate, so it rarely touches prepared foods. Where natural food sources are scarce, keepers can supplement with sinking shrimp pellets or small bits of fish, mussel, or shrimp flesh placed directly under an arm a few times a week. A newly set up tank without established biofilm cannot sustain it, which is why aquarists are advised to wait until the system has matured before adding one.

Tank mates

Peaceful and defenseless, it poses no threat to corals, fish, or other invertebrates and is a good fit for calm reef community tanks. Predatory or invertebrate-eating tankmates such as puffers, triggerfish, boxfish, large wrasses, and aggressive crustaceans should be avoided, since this star has no real defenses against them. It tends to coexist well with sessile invertebrates and simply crawls over them without causing harm.

Breeding

Reproduction in home aquaria is essentially unreported, and this species is not bred commercially. Wild populations reproduce by broadcast spawning, releasing eggs and sperm into the water column, but the resulting larvae are planktonic and have specific requirements that are impractical to replicate in captivity. Almost all specimens in the trade are wild collected rather than propagated.

Health

Because sea stars can look outwardly normal right up until they die, close observation of behavior is more useful than appearance alone for judging health. Warning signs include a body that stops moving entirely, whitish or discolored patches on the skin, arm tips curling upward, or visible tissue discharging fluid, any of which indicate a specimen in decline. New arrivals benefit from being held back at the dealer for a week or more to recover from shipping stress before being introduced to a display tank, and slow drip acclimation over several hours reduces losses from osmotic shock.

Sources

1. Orange Marble Sea Star - Quality Marine
2. Fromia monilis (Orange Star, Orange Marble Star) - Saltcorner
3. Necklace Starfish (Fromia monilis) Aquarium Care | Atlarium
4. Marble Starfish Basics | Tropical Fish Hobbyist Magazine

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