The Upside Down Jellyfish can make a unique and interesting aquarium occupant. It is, in fact, one of the more commonly kept jellies; however, in order to allow these invertebrates to thrive, experts recommend making several modifications to general care plans.

Upside Down Jellyfish will generally thrive in very bright lighting. Although Upside Down Jellyfish rely on symbiotic algae to create nourishment for them through photosynthesis, you may feed your Upside Down Jellyfish solid food once in a while. It is not advisable to reach into the aquarium any more often than necessary in order to avoid contact with nematocysts that can sting when they make contact with the skin. Most people do not have an adverse reaction to such a sting, although some people may experience pain or swelling after contact. The main purpose of these nematocysts seems to be feeding; the frilly tentacles where the stinging nematocysts are located are on the underside near the mouth. Nematocysts are highly specialized cells which fire a tiny dart when disturbed. This is what gives the tentacles a "sticky" feeling. These darts will attach to the prey (or other intruder) and pump toxins into them. Nematocysts also occur in anemones and many corals and are an effective method of capturing prey and discouraging predators.

These invertebrates get their name because they spend most of their lives laying upside down on shallow sandy bottoms exposed to sunlight. Among the frilly tentacle structures are rounded, bladder-like structures, which contain photosynthetic algaes that help the Jellyfish produce its own food. These are often brownish or purplish in color. Their flattened bells pulse gently to carry food and to aid in respiration. Any small organisms caught in the tentacles are generally paralyzed by the nematocysts until the Upside Down Jellyfish eats them. One species of shrimp, apparently immune to the nematocysts of the Upside Down Jellyfish, may live in the tentacles of this species in a symbiotic relationship. It cleans the jellyfish in return for the protection provided by its host.

Upside Down Jellyfish are one of the most common jellies in the pet trade. In the wild, they are normally found in the Caribbean, particularly in western areas of this region. The sight of these invertebrates laying in sandy, shallow areas often thrills divers.

The best aquarium setup for these jellyfish is an aquarium with a wide sandy bottom. The sand layer should be thin. An external wet/dry filter is best but the water intake should be protected to prevent the jelly from becoming trapped. Protein skimmers should be used to keep the water quality up.

Regardless of the set-up you choose, a low current should be present in the aquarium. Metal halide lighting is generally used to help Upside Down Jellyfish thrive, though bright flourescent lighting is also acceptable. Brine shrimp are most commonly offered as food but this is rarely needed.

Most people do not have an adverse reaction to the sting of an Upside Down Jellyfish, although some people may experience pain or swelling after contact. If you believe you are having an abnormal reaction, please contact your physician. Normally, liquids high in ammonium will help neutralize the stinging.

To encourage Upside Down Jellyfish to reproduce, bright halide lighting is important. Low detectable levels of ammonia are also helpful, and many people recommend ceasing filtration to help encourage your invertebrates to breed. The sexually mature life phase of an Upside Down Jellyfish is the medusa, the familiar bell-shaped invertebrate. These medusae produce sex cells for reproduction. After sperm and egg cells combine, the larvae settle at the bottom of the aquarium. These larvae grow into polyps that are similar in appearance to anemones. The Upside Down Jellyfish polyps begin to divide asexually, stacking on top of one another before eventually becoming independent of one another in the ephyra stage. Ephyra are essentially underdeveloped medusae.