Some new hitchhikers have appeared all over my brood stock system in the last few hours and I wanted everyone’s opinion.
I’ve encountered these “miniature jellyfish” before. In fact, I’ve seen them appear from time to time in almost every reef system I’ve ever owned. But never to this extent which has me a little concerned.
Researching online has lead me to believe they are a type of hydrozoid. They start of swimming in the water column much like you’d expect of a jellyfish. They pulse pretty rapidly. Eventually they seem to settle down on the ground and have 5-6 very small tenticles that attach them to the walls or bottom.
Maybe I’m just noticing them because of the bare bottom. I can imagine them blending right in to a normal tank. I’d estimate there are 100 or so in the system. Thoughts?
[quote=“RCA, post:1, topic:2289”]
Researching online has lead me to believe they are a type of hydrozoid.[/quote]
May be a Hydromedusa or a Hydroid in the medusa stage(Class Hydrozoa). They are infact a type of “miniature jellyfish”. Chances are they will dispaer on there own. My guess would be that we don’t see them in reef tanks as much due mostly to lack of food, competition for food, and predation. Typically these guys show up when something new is introduced and won’t stick around for long. They are more likely to survive long term in a wholesalers tank or an LFS where new live rock is transfered in frequently with plankton on board.
Should know that some hydroids can cause harm to humans though. Probably a good idea to avoid touching these guys with your hands.
Any chance we could get a closer up image of them through the glass, so we can more positively ID? Really hard to see. Or perhaps you could bring some in to a meeting so another member can snap macro shots of them?
My guess would be no harm and they will go away on there own.
I have had those before. I thought Ron Shimeck says they are a larval form of something in the tank. worms, or something. They were so cool. swimming up to the surface in pulses and then sinking back down. all day long. like little jellies. How many arms do they have? they look like upside down badmitton shuttles. Right?
Aye, badmitton shuttles. They appear to have eight arms. Each arm has a tentacle growing out of it that looks like it’s used to catch food. I tried taking shots again this morning with a nickle standing next to one of the creatures that attached itself to the front of the tank. Again, we’re looking at it from the underside.
Naw, nothing like that. I vote for the badmitton birdie type thingie, what ever they are. They are cool to watch if you are lucky enough to have some show up in your tank.
