Blubber Jelly
Catostylus spp.
Blubber Jellyfish is a blanket term that refers to multiple species, and they are often all mistakenly grouped under the scientific name Catostylus mosaicus. The multicolored blubber jellies we all know and love come from the Phillipines and are likely an undescribed species of Catostylus. C. mosaicus on the other hand, hail from Eastern Australia. Other Blubber jellies include Catostylus Tagi from Portugal, Catostylus perezei from the Persian Gulf, and Catostylus townsendi from China. This particular guide will focus on the commonly available Phillipine blubber jelly.
Caring for Blubber Jellies
Although once thought to be impossible to keep long term, this largely stemmed from a lack of understanding about their husbandry requirements. Blubber jellyfish are very active and swim briskly, so it's important to feed them often and provide an aquarium with adequate space for moving around.
At this time, Blubber Jellies have not been successfully aquacultured and so all specimens sold are wild collected. This adds a couple of considerations to their care. Wild Blubbers almost always come in with a giant copepod species living on them. Although often described as commensal, they tend to lean more parasitic in captive environments. Feeding on the protective slime coat of their host jellyfish, if left unchecked they can irritate the jelly, possibly leading to holes in the bell. Eradicating them is fairly simple and something a quality jellyfish supplier should do for you. If there seem to only be a few copepods, they can be manually removed with a pipette. But for a more thorough job, medicated dip will do the job. Two Little Fishes Revive dip works great. Fill a bowl with aquarium water and add the correct amount of dip per the bottle's instructions. Move your jellyfish to the bowl and gently stir the water bit. The copepods will all come racing out of the jellyfish and after a few seconds you can remove the jellyfish. Its a good idea to have a second bowl of clean aquarium water to rinse your jellyfish off in before returning it to its aquarium.
Stocking density: Blubber jellies don't have long tentacles to tangle up so they can be kept in fairly dense stocking density. But keep in mind that being such and active jellyfish, they utilize a lot of oxygen and produce a lot of waste. A lower stocking density will be easier to maintain, especially for a home aquarium.
Flow: Blubber jellies are pretty capable of keeping themselves suspended. Start with a medium flow for them and go from there.
Feeding: These guys like to eat a lot! It's best to feed them as often as you can, at least twice per day. Live baby brine shrimp makes a good staple option. Products like OysterFeast and RotiFeast help provide supplemental nutrition.
Compatibility with other species: It's not currently clear if Blubber jellies can be kept with other species.
Temperature Range: 65-75 F
Salinity: Blubber jellies are often shipped in water at 35 ppt or 1.026 SG. It may be more ideal to slowly acclimate them to 19 ppt or 1.014 SG. This works remarkably well for similar species such as Cannonball Jellies and Flame Jellies.
Life Stages
A quick note: I was sent a culture of what is supposedly Catostylus mosaicus. I am still in the process of determining whether these are truly C. mosaicus or some similar species.
