Are we sure these are colonial hydroids?

[afishbestservedcold]

I still dont think these look like athecate hydroids, they look exactly like a Nausithoe species in OP's pic and the others in this thread. mine haven't stung me like OP though...

If you want to keep your hydriods, keep them. But in some aquariums they take over and kill whoever they want. Corals, and anemones cannot fight back. Thriving hydriods want a territory, they are going to win.
Advice is to get rid of them for a reason. This isn't cancel culture.
Having a variety of animals in our aquarium creates a war zone. It's our job to keep it in check.
If someone wants to observe and see they are of no issues in their system. Thumbs up to that person.

 

[Goaway]

I still dont think these look like athecate hydroids, they look exactly like a Nausithoe species in OP's pic and the others in this thread. mine haven't stung me like OP though...

What's important is for people to observe their hitch hikers. Hydriods are a mass family. There's over 2000 species of hydriods. Finding an exact ID on them is not easy. Behavior is most important.

 

[Coral Winslow]

I have the same ******s. They are very invasive. I finally was able to find a source for some Fringeback nudibranch that were in stock. I have battled these guys for going on 2 years. Pilgrim or Lynx nudis would have been my first pick, but I’ll take what I can get. bought all 7 they had, should be here soon. I will follow up here.

 

[advanwoerden]

I have the same ******s. They are very invasive. I finally was able to find a source for some Fringeback nudibranch that were in stock. I have battled these guys for going on 2 years. Pilgrim or Lynx nudis would have been my first pick, but I’ll take what I can get. bought all 7 they had, should be here soon. I will follow up here.

Did the nudis work?

 

[Coral Winslow]

Did the nudis work?

Sorry, just seeing this. No, my skunk cleaner shrimp decided to shred them all. $90 bucks worth of nudis gone in a couple days.

 

[MinnieMouse2]

I have these colonial hydroids. They seem to not harm other corals. They harm me. I was getting arm blistering here and there. Thought I was getting a salt allergy. I hate to wear gloves. One of our local reef members told me what these colonial hydroids were. I spent last night scraping them off the rocks. This morning after a sleepless night My arm is covered in burning welts, hands too. Once you scrap these they spread. They have already spread around the tank. Do not seem to harm the fish, they seemed to not care. I did not see a reaction from fish or clams. This tank is 8 years old and has five clams in it, live fiji rock, lots of baby rock anemones that are beautiful pinks and red, Sps, duncans, hammers, etc. . I am not going to kill the tank. I can not cut down feeding for we have a Mandarin fish that needs to be fed gut-loaded brine shrimp which hydroids love. This is part of reefing that really stinks. I am going to have to wear long gloves all the way up the shoulders and keep the hydroids scraped down, water changed, and hope for the best. I did not find any on the back of the rocks. They are all out front in the light where one can scrape. I am also going to be covering some of the colonies with epoxy. This might be something some people would quit over. Once they are in a system they are in. You have to start over with everything being nuked from skimmer to refugium, to everything. This after I just go Dinos under control in two tanks. I hate these things. I thought they were pretty. I thought they were feather duster-type corals. I was even thinking of moving some to my 125-gallon tank because they look pretty under blue light. Do not make my mistake. See these kill these before they spread. I let my spread.

 

[shakacuz]

i have the smaller, think stalk/stem, all white ones.

 

[dkcr]

I have them everywhere in my 100 gallon tank. They seem to sting my polyps who have been disappearing wherever these nuisance things are. The heads retract inside the tubes and when I touch the tubes they feel hard they don’t move. I haven’t been stung by them.