Digitate hydroids? How bad?

[thrillreefer]

Does anyone know what these stretchy white strings coming out of my live rock are? Very stretchy, not like micro brittle star arms. They’re coming out of rocks and sand, look kinda cool, hopefully harmless


[sorry, GIPHY crushes the quality]

 

[thrillreefer]

Uh oh this thread post #7-10 says digitate hydroids and bad news

white thread, hair like strings coming out of rock

Hello and good morning. I have like white stings coming from behind my rock and its spreading. It can retract. Not a feather duster. the strings are long . Thank you.

www.reef2reef.com

 

[Discovery]

I have them - many of them - as well. Must have been a hitchhiker. They multiply quickly. They do sting corals - I have some zoas that haven’t opened fully in a while and I lost two frags. I have a 24k lepto where one side has black spots where hydroids were and the other side is clean and growing well. I scraped the hydroids off as best as I could and the black spots are fading.

 

[Discovery]

I just added this guy - fringe back nudi. Hope he settles the issue - trying to avoid chemicals.

 

[thrillreefer]

Very pretty too. Where’d you get it?

I’m considering an ORA Pygmy filefish after someone on R2R commented that theirs wiped out digitate hydroids. Friend of mine has one and says good personality too.

So far I haven't noticed a lot of issues from the hydroids so I'm just waiting to see. I actually like how they look, because for some reason they remind me of diving and getting really close up to ocean rock. Tons of tiny life out there.

 

[Discovery]

Ordered from mysaltwaterfishstore down in Florida. Hopefully these guys perform!

 

[ChrisV]

I just added this guy - fringe back nudi. Hope he settles the issue - trying to avoid chemicals.

Does that species eat hydroids? Very neat!

 

[ChrisV]

I had another species of hydroid in a past tank and I tried eradication methods that were fully insane. I never beat them. I'd love to hear about how your sea slug does.

 

[thrillreefer]

I had another species of hydroid in a past tank and I tried eradication methods that were fully insane. I never beat them. I'd love to hear about how your sea slug does.

Digitate ones or colonial? What did you try? Supposedly some angels, butterflies, filefish, maybe foxface will eat them but all anecdotal

 

[ChrisV]

Digitate ones or colonial? What did you try? Supposedly some angels, butterflies, filefish, maybe foxface will eat them but all anecdotal

Colonial. I tried things like removing whole rocks and covering the entire rock in kalk paste, leaving it out of the water for half an hour, rinsing it, and putting it back in the tank. Tried physical removal with stiff bristled brushes. None of that really worked. I did find that removing the rock and hitting it at length with a propane torch could kill them. But they came back so fast. It was a dark time for my hobby.

 

[Discovery]

Does that species eat hydroids? Very neat!

Someone posted on R2R that they worked and also read a few other blogs about their effectiveness- so I’ll give it a try. Will let you know how successful they are.

 

[Casino]

Bumble bee snails eat those also. You can try to break the tube they are in and use putty to cover it up.

 

[ChrisV]

Bumble bee snails eat those also. You can try to break the tube they are in and use putty to cover it up.

Ah interesting, I hadn't heard of using them for hydroids, only vermetid snails.

 

[Casino]

Ah interesting, I hadn't heard of using them for hydroids, only vermetid snails.

They go to town on those aswell. Some have had luck with urchins and starfish and some of the sea slugss also. Read somewhere that clownfish can also hunt these guys down, don't know why they would tho.

 

[thrillreefer]

Bumble bee snails eat those also.

Bumble bees will eat digitate hydroids or will eat colonial hydroids? (And I have both so maybe it doesn’t matter!)

Also just found another thread saying Halloween hermits eat digitate hydroids. But Reefcleaners says they’re herbivores, and come from a genus with several nearly identical species so it sounds hit or miss too.

 

[ChrisV]

If natural eradication doesn't work and you don't own a propane torch, this thread looks informative: https://www.reef2reef.com/threads/here-it-is-fenbendazole-use-against-hydroids.214950/

 

[Casino]

Yeah they'll go for both but I don't think they go for the big ones. It's hit or miss with all the inverts that eat them. Hermits are scavengers and they will eat anything. But again it's always hit or miss

 

[thrillreefer]

don't own a propane torch

Torch sounds the most satisfying!

The colonial hydroids I’ve had on some spots on LR for years and they don’t take over. Kinda pretty with delicate fluorescent polyps. Maybe different cryptic species exist? Because some people claim they’re an invasive scourge and some not. Could settle it by DNA sequencing!

 

[ChrisV]

Torch sounds the most satisfying!

The colonial hydroids I’ve had on some spots on LR for years and they don’t take over. Kinda pretty with delicate fluorescent polyps. Maybe different cryptic species exist? Because some people claim they’re an invasive scourge and some not. Could settle it by DNA sequencing!

Lol. The torch was satisfying at the time, but overall the experience was still negative. And my goodness, the “are you sure you still enjoy this hobby” questions that followed…those were not ideal.

I have no idea why they tend to take off in some tanks and not others. I will say that in that system, I was using live rock that was 10 years old and I had not added new corals in at least four years. There were none that I saw, then just a few….then a few more…then before you know it Chris is out on the lawn like a crazy person taking a torch to his live rock…happened over the course of a few years.

The ones I had were lightly fluorescent with like a greenish blue hue to them and retracted into a sort of leathery tube (especially before burning to a crisp). I think they may have been photosynthetic. Fwiw I did not feed any fine powdered food to the system— so that wasn’t fueling them.

To be clear, I do not advocate for the torch method.

We can’t sequence mine! They are gone. As is that tank.

 

[LisaJulia65]

Lol. The torch was satisfying at the time, but overall the experience was still negative. And my goodness, the “are you sure you still enjoy this hobby” questions that followed…those were not ideal.

I have no idea why they tend to take off in some tanks and not others. I will say that in that system, I was using live rock that was 10 years old and I had not added new corals in at least four years. There were none that I saw, then just a few….then a few more…then before you know it Chris is out on the lawn like a crazy person taking a torch to his live rock…happened over the course of a few years.

The ones I had were lightly fluorescent with like a greenish blue hue to them and retracted into a sort of leathery tube (especially before burning to a crisp). I think they may have been photosynthetic. Fwiw I did not feed any fine powdered food to the system— so that wasn’t fueling them.

To be clear, I do not advocate for the torch method.

We can’t sequence mine! They are gone. As is that tank.

I've got 18 year old live rock that survived being in freezing cold water during a move. I thought for sure they would have died once my tank was set up again in the new house. NOPE. They are still there and exactly as you describe. I am hoping the pulsing xenia i just added will cover the rocks and smother them. Mostly in my 72 it's fish only minus a larger rainbow BTA and a couple watermelon shrooms.