I was inspired to make a thread explaining the care requirements and general info of jellyfish. I'm gonna try to keep this as simple as I possibly can.
To start off I'll give you some basic information about jellyfish.
Jellyfish belong to phylum Cnidaria. They are called Cnidarians because everything in the phylum have a type of specialized stinging cells called cnidocytes I'll talk about these more later. There are three groups of organisms that we use the common name "jellyfish."
Jellyfish have complex life cycles they are not just simply born miny jellyfishes. This picture explains it well.
Now for a little anatomy lesson. Rather than me rambling on and on pointlessly to explain different parts of a jellyfish you can refer to this picture for referrence.
Now to elaborate on the types of Jellyfish.
First is the class Scyphozoa which are true jellyfish. Scyphozoa have tentacles, oral arms, and a very simple nervous system called a nerve net. They drift but can control their movements with pulsations of their bell. Jellyfish have become extremely efficient predators by drifting and catching prey that swims into its tentacles becomes stunned or dies and is then brought towards its mouth by use of cilliated oral arms. Here is a picture of one of the most common Scyphozoans.
This is the true jellyfish Aurelia aurita.
The tenatcles are short and numerous and they have four large oral arms they do not have a velum like in the next classes.
Now we have class Hydrozoa. In Hydrozoans the medusa stage is primarily only used for sexual reproduction. The dominant stage is usually a polyp. Hydrozoans have a shelf made of ectoderm under their umbrella which is called a velum this sets them apart from true jelly fish. Hydrozoans have cnidocytes as well since they are part of the phylum Cnidaria. Here is a picture of a common hydrozoan.
This is a Gonionemus vertens. This is the medusa stage. Below is a polyp stage of a freshwater hydra.
The next class I will mention is Cubozoa. Cubozoa are more commonly called sea wasps or box jellyfish because they appear box like with tentacles concentrated at four corners. This is the most dangerous class of all "jellyfish." They are generally smaller in size and because of that they have much more effective cnidocytes. They also have a velum which makes swimming much more effective. They can actively search for food and swim against currents. For these reasons Cubozoans are the Ferraris of the jellyfish world. Stings from Cubozoans have been known to kill humans. Unlike other "jellyfish," Cubozoans have cnidocyctes on their bell.
Here is a picture of Cubozoan.
[FONT="]Keeping jellyfish is a tough task since they have many requirements. The first probably most obvious requirement is a round tank. Most jellyfish are pelagic so they don’t have any natural obstacles that get in their way so they are very delicate if they were to bump into the side of a square aquarium they have a good chance of dieing.
Tanks
They do make special tanks called kreisels but these are usually around 1000 dollars or so. They are usually rectangular tank with a curved edge on the inside. Here is a picture of a newer kreisel that is not inside a rectangular tank.
Filtration and Circulation
Then there is [/FONT]the filtration and circulation problem. They require very clean water and very constant salinities. They also require a slow steady flow of water in a circular motion around the kreisel to simulate drifting and to keep them from bumping into the sides. The filters have to be very slow moving. You can not at all have any bubbles either in the intake or output because it means there is too much flow which can harm the jellyfish. Not to mention the intake pipe needs to be on the outside of the kreisels curve or have another type of device to keep jellyfish from being sucked in.
Feeding
Jellyfish are simple yet very efficient predators. The feed on planktonic like organisms. They usually catch free swimming copepods. They have no brain to speak of and do not really eat dead food. The food must be alive so that it swims into the tentacles where it is caught. Dead food is not really recommended even though it is possible to feed frozen food. Feeding frozen food recquires that you put a lot of food in the water which causes surges of ammonia. If at all possible it is much better to provide a good supply of live food. Jellyfish are constantly feeding so a constant supply of live food is required.
Dangers of Jellyfish
Jellyfish can be deadly or harmless depending on the species. What makes the difference is the cnidocyte. A nematocysts is the actual barb inside the cnidocyte. It shoots out into the object that touches it and delivers a neurotoxin. Some nematocysts are specialized to curl back after being fired to hold on to the prey. Different jellyfish have different nematocysts. So when cleaning a tank iyou must wear a protective layer. It can be as thin as panty hose or as thick as a wetsuit what ever your preference is you must use some type of protection. Tentacles that are detached from the jellyfish can still sting.
Keeping Jellyfish in the home aquaria
The only type of jellyfish I think a nonprofessional could consider taking care of would be a upside down jellyfish. If you were to keep one you can use a rectangular tank. I would highly suggest it be a species only tank. The tank would need to have a slow circulation and an excellent filtration system along with a refugium. Lighting is also very important since they have a mutual symbiotic relationship with a type of algae. Feeding is still necessary. I would reccomend a similar lighting arrangement as used for coral. Upside down jellyfish can have a bell diameter of up to 10 inches so a wide tank is needed. A shallow layer of substrate should be used.
I hope that maybe you learned something about jellyfish while reading this. Just remember jellyfish aren't the best pets.
To start off I'll give you some basic information about jellyfish.
Jellyfish belong to phylum Cnidaria. They are called Cnidarians because everything in the phylum have a type of specialized stinging cells called cnidocytes I'll talk about these more later. There are three groups of organisms that we use the common name "jellyfish."
Jellyfish have complex life cycles they are not just simply born miny jellyfishes. This picture explains it well.
Now for a little anatomy lesson. Rather than me rambling on and on pointlessly to explain different parts of a jellyfish you can refer to this picture for referrence.
Now to elaborate on the types of Jellyfish.
First is the class Scyphozoa which are true jellyfish. Scyphozoa have tentacles, oral arms, and a very simple nervous system called a nerve net. They drift but can control their movements with pulsations of their bell. Jellyfish have become extremely efficient predators by drifting and catching prey that swims into its tentacles becomes stunned or dies and is then brought towards its mouth by use of cilliated oral arms. Here is a picture of one of the most common Scyphozoans.
This is the true jellyfish Aurelia aurita.
The tenatcles are short and numerous and they have four large oral arms they do not have a velum like in the next classes.
Now we have class Hydrozoa. In Hydrozoans the medusa stage is primarily only used for sexual reproduction. The dominant stage is usually a polyp. Hydrozoans have a shelf made of ectoderm under their umbrella which is called a velum this sets them apart from true jelly fish. Hydrozoans have cnidocytes as well since they are part of the phylum Cnidaria. Here is a picture of a common hydrozoan.
This is a Gonionemus vertens. This is the medusa stage. Below is a polyp stage of a freshwater hydra.
The next class I will mention is Cubozoa. Cubozoa are more commonly called sea wasps or box jellyfish because they appear box like with tentacles concentrated at four corners. This is the most dangerous class of all "jellyfish." They are generally smaller in size and because of that they have much more effective cnidocytes. They also have a velum which makes swimming much more effective. They can actively search for food and swim against currents. For these reasons Cubozoans are the Ferraris of the jellyfish world. Stings from Cubozoans have been known to kill humans. Unlike other "jellyfish," Cubozoans have cnidocyctes on their bell.
Here is a picture of Cubozoan.
[FONT="]Keeping jellyfish is a tough task since they have many requirements. The first probably most obvious requirement is a round tank. Most jellyfish are pelagic so they don’t have any natural obstacles that get in their way so they are very delicate if they were to bump into the side of a square aquarium they have a good chance of dieing.
Tanks
They do make special tanks called kreisels but these are usually around 1000 dollars or so. They are usually rectangular tank with a curved edge on the inside. Here is a picture of a newer kreisel that is not inside a rectangular tank.
Filtration and Circulation
Then there is [/FONT]the filtration and circulation problem. They require very clean water and very constant salinities. They also require a slow steady flow of water in a circular motion around the kreisel to simulate drifting and to keep them from bumping into the sides. The filters have to be very slow moving. You can not at all have any bubbles either in the intake or output because it means there is too much flow which can harm the jellyfish. Not to mention the intake pipe needs to be on the outside of the kreisels curve or have another type of device to keep jellyfish from being sucked in.
Feeding
Jellyfish are simple yet very efficient predators. The feed on planktonic like organisms. They usually catch free swimming copepods. They have no brain to speak of and do not really eat dead food. The food must be alive so that it swims into the tentacles where it is caught. Dead food is not really recommended even though it is possible to feed frozen food. Feeding frozen food recquires that you put a lot of food in the water which causes surges of ammonia. If at all possible it is much better to provide a good supply of live food. Jellyfish are constantly feeding so a constant supply of live food is required.
Dangers of Jellyfish
Jellyfish can be deadly or harmless depending on the species. What makes the difference is the cnidocyte. A nematocysts is the actual barb inside the cnidocyte. It shoots out into the object that touches it and delivers a neurotoxin. Some nematocysts are specialized to curl back after being fired to hold on to the prey. Different jellyfish have different nematocysts. So when cleaning a tank iyou must wear a protective layer. It can be as thin as panty hose or as thick as a wetsuit what ever your preference is you must use some type of protection. Tentacles that are detached from the jellyfish can still sting.
Keeping Jellyfish in the home aquaria
The only type of jellyfish I think a nonprofessional could consider taking care of would be a upside down jellyfish. If you were to keep one you can use a rectangular tank. I would highly suggest it be a species only tank. The tank would need to have a slow circulation and an excellent filtration system along with a refugium. Lighting is also very important since they have a mutual symbiotic relationship with a type of algae. Feeding is still necessary. I would reccomend a similar lighting arrangement as used for coral. Upside down jellyfish can have a bell diameter of up to 10 inches so a wide tank is needed. A shallow layer of substrate should be used.
I hope that maybe you learned something about jellyfish while reading this. Just remember jellyfish aren't the best pets.
