digitate hydroids

How about some pics so everyone chimes in on the right subject. Also so those that don't have them will know what to watch for.

The flamethrower was my personal favorite technique for taking care of these guys.

Everything is related if you go back far enough.

Corals are in phylum Cnidaria. So are jellyfish and hydroids. Class Hydrozoa contains hydroids and some corals. Class Scyphozoa contains jellyfish. Class Anthozoa contains some corals and anemones. So, all the claims that hydroids are related to corals/jellyfish/anemones are true. They're stinging-celled organisms..."cnidarian" literally means "stinging creature" in Latin (technically it translates to "sea nettle"...but you get the idea).

Here's a photo of one in my tank, unexpanded. You can see all the stinging cells. I have a video of it somewhere...it's quite insanely hilarious to watch as it expands and contracts.



So, since they can sting, then they can bother sensitive creatures (namely seahorses). They usually coexist somewhat with corals, although they can irritate them. Theoretically they can sting humans too, but I imagine it would be unnoticeable except in highly sensitive people. They also use their stinging cells to collect food like a fishing reel.

As far as what eats them and what doesn't, well...probably what eats coral may eat them (but maybe not since they're so small). They'll also wax and wane with your nutrient level (they filter-feed). I used superglue or epoxy over the ones I had that were hidden in a rock.

Hope that helps.

He hasn't been online since posting this, or I'm sure he would have posted his appreciation.

I for one always appreciate detailed feedback. And that picture is bad-a.

Looks like he's having some more problems. He lives down this way in Orem and needs his water tested(not with the strips he has) so I have offered to test it here in the next few days. Maybe I can swing by his place and get some better pics of what he is dealing with...

The ones you're seeing on the glass are probably Stauroclaudia. They're related...so they sting...but they are pretty much benign except in rare cases. They'll usually wax and wane as your tank matures.

I wouldn't worry about it. I'm pretty sure every single one of us has had them at some point, and they always disappear on their own.

Glass is clean, water changed.
Still more digitate than i am comfy with. But i am patiently waiting.

So, how about colonial hydroids? I was going to make a thread asking about them but maybe since we've already got an active hydroid thread going... I've got three 'colonies' on my LR, I was thinking about just chiseling off the chunk of rock they're connected to.