There have been a few times that I’ve been asked how to care for jellyfish. And, long story short, it’s complicated! In this short article, I describe the complications of keeping these fascinating creatures in captivity. Some creatures should just stay in the wild, and the jellyfish usually is one of them.
Meticulously keeping up with maintenance on the aquarium, frequently testing your parameters and cultivating live food are all necessary tasks that make jellies hard to keep. These definitely aren’t creatures that you can throw in a tank and forget about. Jellyfish are only recommended for expert aquarium keepers due to their many requirements. They are very demanding compared to most other invertebrates and I definitely don’t recommend a jellyfish tank being your first tank.
However, if kept in proper conditions, some people say you can have jellyfish for many years. Proper water flow is key to successfully keeping jellyfish. The current must be gentle and it shouldn’t create any air bubbles (which can be deadly to the jellyfish). Jellies require pristine water conditions so there is no room for error in water quality. It is crucial to ensure that your tank is 100% cycled before adding any jellyfish as the slightest ammonia or nitrite spike easily can be fatal.
Some manufacturers produce cylindrical aquariums specifically made to house moon jellys. The round shape of the tank produces a circular water flow pattern which keeps the animal suspended and prevents it from getting stuck to the drains. A few manufacturers offer all-in-one kits for keeping them. These kits (when well designed) create an aquarium made specifically for jellyfish.
Most jellyfish are carnivorous and will eat different zooplankton; the bigger ones will eat small fish. Live decapsulated brine shrimp are a great food for jellies. Keeping up with brine shrimp cultures is important as most jellies will not accept frozen foods. Luckily, it is fairly easy to set up a brine shrimp hatcher at home; there are tons of videos online to show you how to do this step by step. You can otherwise regularly order live, freshly hatched, decapsulated brine shrimp to have shipped to your door (i.e. Nano Brine).
Honestly, any time a customer asks me how to set up a jellyfish aquarium, I typically steer them away from the thought (especially if they have never kept a saltwater tank). It is not something beginners should undertake as it may not leave them with the best impression of this hobby. As delicate as jellies are, I would rather help a customer set up a stunning conventional saltwater aquarium than encourage them to take on the substantial challenge of keeping them. I usually recommend setting up a standard saltwater tank to start, and if after a year they find it fairly easy to keep, then they can reconsider keeping jellyfish. The moon jelly is one of the best first-time jellyfish species to work with.
It takes a special person to be able to cater to the needs of jellyfish. Most people that plan on keeping jellyfish do their own research and become familiar with all aspects of jellyfish husbandry. These are live animals that we are keeping at home and it is our job to take the absolute best care of them. Most saltwater fish/invertebrates, including most jellyfish, are still wild caught so they are coming from their natural environment and going right into our small home aquariums!