Can You Keep Jellyfish in an Aquarium? A Beginner’s Guide to Jellyfish Tanks

 

Published: Oct 15, 2026 | Category: Aquarium Hobby

There is something hypnotic about watching jellyfish drift silently through the water. For decades, these graceful ocean drifters could only be admired in large public aquariums. Today, thanks to specially designed aquarium systems, it is absolutely possible to keep live jellyfish in your home aquarium. But before you rush to buy your first jellyfish, there are critical differences between a regular fish tank and a jellyfish setup.

Why a Standard Fish Tank Won’t Work

Jellyfish bodies are extremely soft and fragile. A typical rectangular aquarium has sharp corners, turbulent pump flow, and filter intakes that can trap, tear, or injure jellyfish easily. Bubbles are another big risk; trapped air under their bell can damage their body and even kill them.

The ideal home for jellyfish is called a kreisel tank. This rounded, curved aquarium creates smooth, circular laminar water flow that keeps jellyfish gently suspended, just like in the open ocean. There are no sharp corners for them to get stuck in, and protected filter screens keep jellies away from pump intakes. Compact desktop kreisel kits are now widely available for hobbyists, making jellyfish keeping more accessible than ever.

Best Jellyfish Species for New Hobbyists

If you are new to jellyfish, Moon Jellyfish (Aurelia aurita) are the top recommendation. They are hardy, affordable, and adapt well to home kreisel aquariums. Their translucent bells glow beautifully under soft LED lighting, turning your tank into a stunning living display.

Other options for experienced keepers include blubber jellyfish, but these require larger tanks and more precise water control. Never try to keep dangerous species such as box jellyfish at home.

Key Water & Equipment Requirements

Jellyfish are saltwater creatures, and stability is everything. Small swings in water parameters can quickly stress them.

  1. Salinity: Keep specific gravity around 1.023–1.025 (30–34 ppt). Use a refractometer for accurate measurement. Only use high-quality marine salt mix with RO/DI water.
  2. Temperature: Moon jellies prefer cool water, roughly 16–21°C (60–70°F). Most setups need a water chiller to avoid overheating from room temperature or tank LEDs.
  3. Water Quality: Ammonia and nitrite must stay at zero. Test water regularly and perform partial weekly water changes (10% every 7–10 days) to control nitrate buildup.
  4. Lighting: Jellyfish do not need bright light to survive. Soft RGB LEDs are mainly for visual enjoyment, to show off their translucent bodies. Avoid strong lighting that heats up the tank.

Feeding Your Jellyfish

Jellyfish feed on tiny live foods. Newly hatched baby brine shrimp and rotifers are the staple diet for moon jellyfish. Feed them 1–2 times per day. You can tell they have eaten when their four horseshoe-shaped oral arms turn orange from food. Remove leftover food quickly; uneaten food pollutes saltwater and ruins water stability. Never use coarse dry fish food, which can block their digestive system.

Important Safety & Tank Mate Rules

  • No tank mates: Do not mix jellyfish with regular fish, shrimp or corals. Jellyfish stinging cells can hurt other creatures, and fish may tear the jellyfish bells. A jelly tank should be a species-only aquarium.
  • Handling: Never touch jellyfish with bare hands or scoop them with a fine net, nets will tear their soft tissue. Use a smooth plastic cup to move them when needed.
  • Sting warning: Moon jelly stings are mild for most people, but sensitive skin may still react. Always wear gloves during tank maintenance.

Is Keeping Jellyfish Hard?

Jellyfish are not “set-and-forget” pets. They demand stable water chemistry, specialized gear, and consistent weekly maintenance. They are easier to keep than many people assume — once you master the kreisel tank system and maintain steady water conditions, moon jellyfish can live for many months in your aquarium.

Final Thoughts

A jellyfish aquarium is more than decoration; it is a peaceful window into the ocean. If you love aquariums and enjoy careful routine maintenance, a kreisel tank with moon jellyfish can be an incredibly rewarding hobby. Just remember: the tank design, gentle flow, and stable saltwater are far more important than the jellyfish themselves. Get the setup right first, and these silent floating wonders will transform your space.