The tiled (or marble, candy cane, necklace, seabisquit) sea star (Family Goniasteridae) seems at a glance to be an easy choice for the marine aquarium. It is fairly commonly available in the trade, costs relatively little to purchase, is very beautiful and can even eliminate some detritus and nuisance algae. Moreover, by all accounts, it is very reef safe. Still, it is not for everyone. The tiled sea star is a sensitive animal that all-too-often quickly perishes in unseasoned or poorly maintained aquarium systems.
Fromia monilis has an extraordinarily wide range; it occurs throughout the Indian and western Pacific Oceans, from New Caledonia and Palau to Okinawa, the Philippines and Indonesia as well as the Red Sea and Australia. It is a shallow, inshore species usually found on rocky habitats from 0-40 meters deep, and is rarely found below 51 meters deep.
The species usually grows to about five or six inches in diameter, though specimens as large as a foot have been reported. Different color forms are characteristic of different regions (to further complicate identification, the species often resembles closely related species such as F. nodosa). The most common form has a brilliant red background hue with beige plates covering the base of each arm and whitish highlights over the knobs toward the tip of each arm.
The tiled sea star is an omnivorous scavenger, feeding on small or sessile invertebrates, detritus and bacterial or algal biofilms. It does best in seasoned aquaria that have well-developed biofilms and pockets of detritus. For this reason it should only be added to a mature system of at least 30 gallons in size. All too often, they slowly starve to death in captivity, dying within a year or so with no clear warning to the keeper. As such, it is a good idea to supplement its diet with flake foods and/or very finely chopped meaty items; the food should be placed very near the slow-moving sea star’s reach so that it is not stolen by a tankmate.
This sea star does not just find enough nutritious food in any “dirty” tank, as water quality must be optimal. Stability is also crucial, as sudden changes in the physical or chemical environment can stress and kill this delicate creature. Hence, appropriate precautions should be taken when necessary, particularly during acclimation (drip acclimation for at least two hours is recommended for this species). Even top-off, water changes and chemical additions must be done very carefully. The animal should be handled as little and as gently as possible and should never be exposed to air. Avoid temperature swings, maintaining a steady temperature somewhere from 72-78°F. Specific gravity should be similarly closely controlled, maintained steadily at a specific gravity of 1.024-1.025.
Though it will not harm any of its tankmates, it may be attacked by certain types of crab or fish (e.g. triggerfish). As always, stock carefully.
For those with clean, stable aquarium systems of over a year in age, F. monilis can add a significant amount of beauty and character. With adequate attention paid to their more broad requirements, this species is very undemanding in its care and can provide an aquarist with many years of enjoyment.