Do these jellyfish attack dwarf seahorses? And how would I get rid of them?

nathan212178 · Jun 2, 2022

Hello I’ve been wanting a dwarf seahorse tank for about a year now but I’ve been having trouble with pests, specifically these small jellyfish and anemones, even taking down my last tank and starting over again because of them though I’ve already delt with the anemones, the jellyfish occupation still concerns me. I want to know what I can do to get rid of these jellyfish without using chemicals if possible and I have been taking them out manually and even looking at them through my schools microscope to get a better view of them. My only conclusion is that the tank conditions are perfect for the jelly’s to catch food since it’s a low flow style tank and even if I change it to a higher flow I’m not sure if they will come back if I add the dwarfs in.
the tank is a 10G and I’ll add pictures of the jellyfish.Jelly Jelly2
I’ve been planning on adding a small mandarin to take out the copepod population or to add another predator though im not sure if it will help and will only be in it temporarily and not long term, and I have live food and dry food for it if needed.

brandon429 · Jun 2, 2022

Eight lobes isn't out of the realm of hydra/ hydroids

They're known hitchhikers on anything hardscape or water transfer from an existing tank with hydroids. All reef tanks are assumed to be carrying lots of them

So a common exclusion option is building an all dry rock, bottle bac cycle system. That gets a tank ready that carries bioload and never vectors for hydroids. Don't add anything to the tank that came wet from another tank.

Some people consider hydroids so inevitable they use only non rock, plastic filtration setups or uplift sponges that can be rinsed free of medication between tank rotations of panacur treatments.

nathan212178 · Jun 4, 2022

brandon429 said:
Eight lobes isn't out of the realm of hydra/ hydroids

They're known hitchhikers on anything hardscape or water transfer from an existing tank with hydroids. All reef tanks are assumed to be carrying lots of them

So a common exclusion option is building an all dry rock, bottle bac cycle system. That gets a tank ready that carries bioload and never vectors for hydroids. Don't add anything to the tank that came wet from another tank.

Some people consider hydroids so inevitable they use only non rock, plastic filtration setups or uplift sponges that can be rinsed free of medication between tank rotations of panacur treatments.

thank you very much!!!! I will keep that in mind, it had started with and all dry system yet I added some macro algae from a tank which they most likely came from. What would be the cure to reduce their population? A chemical like panacur was something in mind that I would like avoiding but if I need to treat the tank with it I will. And again thank you

brandon429 · Jun 4, 2022

I have heard of no way to avoid panacure use if there are any breaks in the chain of handling from systems guaranteed hydroid free, which is all marine tank arrangements that didn’t originally begin with complete exclusion techniques such as dry start + only stocking materials that cannot vector hydroids.

Excluding hydroids from wet marine surfaces is like trying to exclude bacterial transfer when handling materials between tanks, these organisms are ubiquitous in nature.

one might then wonder: if the hydroids are so dangerous how do these horses survive in nature

in nature, hydroids have micro predators to control populations- exclusion zones exist among diverse substrates where algae don’t like to attach, or other benthic creatures like tiny stinging hydra…some plants exclude benthic attachment like an allelopathic response

horses can choose to congregate in these areas

Baby seahorses are most at risk, large ones not as much. the stinging micro hydra reduce viable population numbers as seahorses undergo the birth + growth cycle.

baby seahorses are lost to hydroids in nature just not to such a degree as to lose the species.

JCM · Jun 4, 2022

brandon429 said:
Eight lobes isn't out of the realm of hydra/ hydroids

They're known hitchhikers on anything hardscape or water transfer from an existing tank with hydroids. All reef tanks are assumed to be carrying lots of them

So a common exclusion option is building an all dry rock, bottle bac cycle system. That gets a tank ready that carries bioload and never vectors for hydroids. Don't add anything to the tank that came wet from another tank.

Some people consider hydroids so inevitable they use only non rock, plastic filtration setups or uplift sponges that can be rinsed free of medication between tank rotations of panacur treatments.

What does "never vectors for hydroids" mean? I've never seen "vector" used in this sense.

I agree Hydroids are almost inevitable, even starting with all dry rock it's easy to inadvertently bring some in on almost any addition to the tank.

EeyoreIsMySpiritAnimal · Jun 4, 2022

nathan212178 said:
Hello I’ve been wanting a dwarf seahorse tank for about a year now but I’ve been having trouble with pests, specifically these small jellyfish and anemones, even taking down my last tank and starting over again because of them though I’ve already delt with the anemones, the jellyfish occupation still concerns me. I want to know what I can do to get rid of these jellyfish without using chemicals if possible and I have been taking them out manually and even looking at them through my schools microscope to get a better view of them. My only conclusion is that the tank conditions are perfect for the jelly’s to catch food since it’s a low flow style tank and even if I change it to a higher flow I’m not sure if they will come back if I add the dwarfs in.
the tank is a 10G and I’ll add pictures of the jellyfish.Jelly Jelly2
I’ve been planning on adding a small mandarin to take out the copepod population or to add another predator though im not sure if it will help and will only be in it temporarily and not long term, and I have live food and dry food for it if needed.

The seahorse forum might be a better place to post this... Hopefully you can get the answers you need