Jellyfish eat a variety of foods both in the wild and in your tank. They eat small plants, phytoplankton, zooplankton, fish eggs, and other small fish called larvae; they also eat the planktonic eggs and young stages of many different kinds of marine animals. Some jellyfish even eat other jellyfish.
Before we get into what jellyfish eat let us take a look at jellyfish as a species.
What is a Jellyfish?
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Jellyfish have been on Earth for millions of years, even before dinosaurs. Jellyfish are mostly made of water and protein and in some parts of the world, people eat jellyfish.
The name jellyfish is a general term used to describe an animal made of jelly-like material, gelatinous material. Some fish are classified as “jellyfish” when in fact they are not true jellyfish, they just have a common jellyfish form. “True jellyfish” are scyphozoans (from the class Scyphozoa), and other jellyfish are hydrozoans (from the class Hydrozoa).
Jellyfish are found in every ocean in the world, they are not strong swimmers so go where the ocean currents push them. When found in a group they are referred to as a jellyfish bloom.
They can vary in size from tiny jellyfish, the size of a pin-head, to some of the larger jellyfish which are larger than a human. Their lifespan varies greatly from only a few days to a couple of years.
The most common jellyfish both in the wild and as pets are the moon jellyfish also known as the common jellyfish, Aurelia Aurita, or the saucer jelly.
What Do Jellyfish Eat?
Jellyfish are carnivorous, meat-eating, fish, and are referred to as opportunistic predators meaning they will eat anything that comes their way but are not hunters. Jellyfish will eat any live food or tiny sea animals that will fit in their mouth.
What do jellyfish eat in the wild?
As mentioned earlier jelly are not very good swimmers and if you have ever seen one in the wild you probably noticed they pretty much just float with the current. While floating jellyfish wait for their floating sea animals to get tangled in their tentacles or sung by them.
The jellyfish stinging tentacles have thousands of stinging cells that are full of venom which they inject into their prey upon contact leaving the victim stunned, paralyzed, or dead depending on the venom dose and the size of their prey.
Besides a jellyfishes unusually shaped body jellyfish are best known for their sting which is how they capture their prey and is their defense mechanism. Jellyfish tentacles are like poisonous spears when contacted by an intruder they shoot with an explosive force.
It exerts over 550 times the pressure of Mike Tyson’s strongest punch to inject venom into the victim.
Once the prey is stunned the jellyfish will bring it into its mouth, which is a small hole in the bottom of the body, often using their oral arms to lead the food into the mouth.
What do pet jellyfish eat?
In the wild, jellyfish feed on plankton, fish eggs, smaller jellyfish, any small, floating creatures that get in its path.
For home jellyfish aquarium food, there are a number of jellyfish specific powdered foods available from aquarium stores. Jellyfish like hatched baby brine shrimp and many experienced hobbyists use this as a supplement along with the powered food.
What Do Baby Jellyfish (Ephyrae) Eat?
Baby jellyfish have a different diet than adult jellyfish.
Baby jellyfish have more limitations on their diet and hunting grounds than adult jellyfish. Due to their small size and mouth, they can eat only small food particles, small eggs or larvae, or even other ephyrae.
A baby jellyfish is only 1-2 millimeters in size and the bell has not developed, so most people do not know they exist. Many people refer to a small adult jellyfish as a baby because of its relative size.
If you purchase a “baby” jellyfish that has a developed bell it is really a smaller jellyfish. Usually, these small jellyfish are fed brine shrimp eggs or small shrimp, freshly hatched brine shrimp.
What Do Adult Jellyfish Eat?
Adult jellyfish referred to as medusae, are not picky eaters, although they are not scavengers who will eat dead animals, will eat any living thing they can get into their mouth.
In the wild, they eat surrounding plankton, zooplankton, small eggs, baby brine shrimp, other jellyfish.
Jellyfish Food Options
Brine shrimp – they produce dormant eggs, known as cysts. The cysts may be stored indefinitely and hatched on demand to provide a convenient form of live feed for larval fish and crustaceans. Brine shrimp are an excellent live food for jellyfish allowing them to feed until the food is depleted.
Many fishkeepers raise their own brine shrimp to keep costs down and for convenience.
Crustaceans (like krill) – Krill are small crustaceans found in all the world’s oceans.
Eggs of Fish
Larvae
Mollusks
Pre-packaged jellyfish food
Small fish
Sea snails
How Often Should I Feed My Jellyfish?
Jellyfish fish need to be feed at least once a day, but more frequent, smaller feedings work well.
In the wild jellyfish graze on their food since they can only eat what comes along. They digest their food quickly and have no stomach, or they would not be able to float.
By feeding them a diet of live food they are able to eat for a longer period of time by catching the live, swimming food.
Summary of What Jellyfish Eat?
Jellyfish will eat any living thing it can get into its mouth.
Many jellyfish species are available at local pet stores and fish shops and these shops usually have an assortment of jellyfish food.
Word of warning: The venom of one box jellyfish can kill a human in under five minutes, making it one of the most potent venoms of any animal in the world.
Jellyfish prefer live food such as Brine shrimp, Crustaceans, small shrimp-like krill, eggs and larval stages of larger animals, Larvae, Mollusks, Pre-packaged jellyfish food, Small fish, and Sea snails but also eat dried planktons or even dried planktonic mix all of which can be purchased at pet stores or online.