Jellyfish are fascinating creatures, so it’s no wonder they’ve found their way into our homes. They are captivating animals but require an expert-level keeper to maintain the pristine water conditions they need to thrive. A jellyfish aquarium differs from a fish tank and needs lots of specialized equipment. If you’re curious about having one of these unique critters in your life, let’s take a deeper look at the facts about keeping pet jellyfish below.
Keeping a Jellyfish Can Prove Challenging
Keeping a pet jellyfish is rewarding but not a good idea for first-time fish owners. They are saltwater creatures, and these tanks require more intensive care than freshwater ones. If you’re new to the game, try working with a saltwater fish aquarium for a year to gain some experience before diving straight into keeping jellies. These creatures also need pristine water conditions with weekly cleaning and water testing, which can be overwhelming for beginners.
The next obstacle when keeping jellies is their food supply. They are carnivores and eat zooplankton and even small fish. The best diet for pet jellyfish is live brine shrimp; they usually refuse frozen or dry food. Jellyfish keepers often produce brine shrimp at home in a hatchery. You can also buy live food, but jellies eat a lot, which can be expensive.
Pet jellyfish also need a cylindrical aquarium because they depend on a circular current to suspend in the water. You can’t keep them in a square fish tank because they will get trapped in the corners and sucked into filters.
Jellyfish Have Traits Not Conducive to Home Aquariums
Contrary to their name, jellyfish are marine invertebrates belonging to the Cnidarian phylum – not fish. They are genetically closer to anemones, plankton, and corals than fish. These fascinating sea creatures are ancient species, and at 505 million years old, they lived a long time before the dinosaurs. Jellyfish are up to 98% water and don’t have a heart, bones, brain, or eyes. The box jellyfish is an exception – it has 24 eyes and 360-degree vision. Jellyfish “see” through light-detecting sensors, which give them blurred vision.
Jellyfish have a basic digestive system with an opening in the center of their body that connects directly to the stomach. After digestion, the jellies excrete waste from the same hole. They have a complex nervous system spread throughout their body and depend on this for hunting and motion. They are incredibly delicate and sensitive, but they can also be deadly. Almost every species has stinging tentacles to catch prey. Jellyfish are a venomous sea creature, and most stings are harmless to humans, but some are potentially lethal.
As you can imagine, with all these traits, it’s very difficult to meet a jellyfish’s needs in captivity.
Jellyfish Have Very Specialized Care Needs
While jellies are a unique creature to add to your tank, they are delicate and difficult to care for. They need pristine water conditions, a super gentle current, and no air bubbles in the tank. Air bubbles can potentially kill jellyfish. You must keep them out of direct sunlight, and you can’t keep them with other sea creatures; you can only keep them with jellyfish of the same species. You must feed them once or twice daily and give them only what they can eat in 15 minutes. Jellies produce a lot of waste, and overfeeding can make the water toxic.
Jellyfish need a high-quality filtration system, and you must test the aquarium water weekly for ammonium and nitrate levels. You should also do a weekly 20% water change. They prefer cool water, usually between 53 and 64 Fahrenheit, and generally don’t need a heater. The challenge is keeping the water cool rather than warm because the average room temperature is around 68 Fahrenheit. You can’t use standard tap water for jellyfish – you must use distilled water or a reverse osmosis system to remove impurities.
The Best Domestic Jellyfish Species
There are over 2,000 jellyfish species, but not all adapt to captivity. The most popular domestic species is the moon jellyfish. You can find plenty of care information about them because they are the most common domesticated species. They are popular because they are adaptable, have a striking appearance, and are easier to maintain.
The moon jellyfish grows up to 12 inches, and their sting isn’t harmful to humans. They are a striking opaque color with mesmerizing movements, and watching them can help reduce stress. In the wild, most jellyfish have a seasonal lifespan of around 18 months but can live longer in captivity. The moon jellyfish lives, on average, two years. These days, professional jellyfish breeders produce domesticated jellyfish in aquariums. But, before their increased popularity, many were caught in the sea.
Other jellyfish species that do well in aquariums include:
- Atlantic sea nettle jellyfish
- Leuckartiara octona
- Australian spotted
- Blue cannon ball
- Fried egg jellyfish
- Purple striped
- Dwarf lion’s mane
- Lactides
Six Fascinating Facts About Jellyfish
On the surface, jellies seem like simple lifeforms, but we’re constantly learning that there’s much more to these creatures than meets the eye. Take a look at these fascinating facts about jellyfish to learn more:
1. If the water is too hot or cold, jellies turn inside out.
2. Some jellyfish are bioluminescent, meaning that they glow in the dark.
3. The Australian box jellyfish is one of the deadliest creatures on the planet. Some jellyfish are lethal, but most stings don’t harm humans. Depending on the species, some stings cause pain and skin irritation.
4. The smallest jellyfish species is the Irukandji, which is just 0.2 inches, and the lion’s mane is one of the largest at 6.5 feet.
5. Some jellyfish, such as the malo kingi, have just four tentacles, while others, such as the mighty lion’s mane, have up to 1,200.
6. The immortal jellyfish gets its name because it can revert to an earlier stage in life. It does this to recover from illness, starvation, or injury.
