Species group: Jellyfish
Other common names:
Scientific name: Sanderia malayensis
Long, graceful tentacles and a hardy disposition (but “hardy” by jellyfish standards only!) have rendered the Amakusa Jellyfish a great favorite of marine invertebrate fans. Although not a “beginner’s species”, this magnificent creature does well for those with the experience and facilities to meet its needs.
The Amakusa Jellyfish is found in the coastal waters and bays of the East China Sea and Sea of Japan.
Appearance / health:
The white to brown body reaches 20 cm. (8 in) in diameter, and trails flowing tentacles that may exceed 91 cm (36 in) in length.
The Amakusa Jellyfish is among the hardiest of the commonly-kept jellyfish, but still requires a skilled care-taker. Poor water quality, starvation, and inappropriate aquarium design (see below) are the most common causes of fatalities. Jellyfishes cannot tolerate copper-based medications, ammonia, or nitrites.
Behavior / temperament:
The Amakusa Jellyfish remains continually in motion, and must be able to do so in the aquarium. Its sting ranges from mild to painful, and the possibility of individual sensitivities or serious allergic reactions must be considered. Jellyfishes are best housed only with others of their kind, as their stings can injure or kill various invertebrates and fishes.
Amakusa Jellyfish should be kept in a Kriesel, which is a circular aquarium specifically designed for jellyfish. Kriesels are equipped with a filtration and pump system that creates the type of current flow that is essential for keeping jellyfish in motion and feeding in the water column. The tank should be fee of coral and such, and lightly stocked, as this jellyfish easily becomes entangled in decorative structures and the tentacles of tank-mates.
The following water quality parameters are critical to long-term health:
Specific Gravity (Salinity): 1.023-1.0205; Temperature: 20-25 C (68-77 F); pH: 8.1-8.4; Alkalinity 8-12 dKH; Ammonia/Nitrites: 0; Nitrates: below 5 mg/l. Calcium, iodine and other trace elements should be added as suggested by the product manufacturer.
Amakusa Jellyfish seem to take live food only, with other jellyfishes being their preferred diet. In public aquariums, specimens reared on a diet of Moon Jellyfish do very well and grow rapidly. Other acceptable foods include brine shrimp, zooplankton, Mysis, and small fish. Brine shrimp should be nutritionally enriched with a commercial algae-based diet designed for that purpose (i.e. Selco) beforehand.
Amakusa Jellyfish reproduce sexually and asexually, going through several stages that differ greatly in appearance and lifestyle before becoming an adult, or medusa. Survival of the larval stages seems to depend upon a ready availability of plankton-based foods.
Written by Frank Indiviglio