DIGITATE HYDROIDS - See this? Kill it now.

EnderTurtle

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Well I have semi-horrible news.

I've got digitate hydroids. What are digitate hydroids you ask? They're a type of cnidarian like our corals, except they look like a clear worm with little bubbles on the end. During the day they will swing their arm around to filter feed and catch copepods. At night they really go crazy and all of them will extend and sway around, trying to catch prey. Not to be confused with colonial hydroids. Those will kill your tank for sure.

This is what they look like.

IMG_4214copy.jpg


How bad are they?

Well there are mixed reviews. Some people have taken down their entire tank, and acid bathed all of their equipment trying to control these. It's also believed that they will kill sps corals, zoanthids, and small benthic fish.

Other people say they are harmless and will not affect corals and will go away. Some people who have followed this idea have let the population of digitate hydroids in their tanks explode.

While some people have noticed that their 20 or 30 digitate hydroids disappeared completely the next day.

I first noticed ONE of these in my tank. It came with a ball of Chaeto algae that I got from a person on reefcentral. I should have crushed this thing with an iron fist that day. But since I wasn't able to find any clues to identify this thing when I googled "white stringy worm in reef tank", I LEFT IT ALONE.

Then a month later there was another digitate hydroid in my tank. I thought oh well theres just one. Now 6 months later there are probably 20 in my display tank. Swaying around. I dont know if I should attack this thing. It doesnt appear to prefer light and does just fine in the dark. That being said, it's probably behind and under my rockwork now. Making me feel that attacking it is pointless now. I should have dropped a nuclear bomb on this thing when there was just one.

The population boom occured about the same time as my 3rd week without water changes. I'll do some nitrate and phosphate tests now.

I don't see any damages to corals but hopefully this doesn't kill my tank. I might quit reefing for a while if it does start bothering my corals.

Feel free to chime in if you have dealt with this or if you know about them.

Also if you notice just one of these in your tank. KILL IT NOW. Cut it at the base and suck it out or take the rock out and blowtorch it. It will save your the worry.
 
I have tons of these in my tank and was also unable to find out what they were. I have a mixed reef and there is probably one of these touching almost every coral I have. Not one has caused a problem or any damage and I really don't even notice them anymore, other than there is a lot of them. Let me know if yours cause any damage or if you figure out a way to eradicate them.
 
I've never ever seen one of these and I just spent a long time looking at my tank and could not find any. How do you know it's from the chaeto I gave you? Maybe it came from a coral you got? Do they stay attached to rocks or do they float around the tank?
 
Well I looked at the chaeto after you gave it to me and I only had two frags in my tank which didnt have it. It was living on the chaeto for a while and just recently started expanding to my display.

It probably died out in your tank and remained in the chaeto. Check your chaeto. When there is light it usually shrivels up. At night it will sway around.

They stay attached. They can attach to glass, algae, rock
 
Maybe something in my tank is eating them? Maybe my cleaner shrimp eats them? Have you read about anything that eats them that you could get?
 
Its okay I dont blame you. These things happen. Ive read that certain shrimps will eat them. Fox faces eat them. Copper banded butterflies.
 
Okay, well that would explain it, good ole foxface eats everything. Might be too large for your tank though. Even mine sometimes looks like he wants more room to swim than my 6 foot tank.
 
@EnderTurtle
I'm in the same boat you were, I'm thinking these are the worst.

So your digitate hydroids just went away? Did you do anything or add anything special to get rid of them?

@alb_56 who wrote on this thread mentioned he still has them.
 
I might have just seen one of these guys in my cheato. I tried sucking it using a syringe but didn't work. Looks like the other end of it is holding tight to some cheato? What's the best was to remove it?
 
I might have just seen one of these guys in my cheato. I tried sucking it using a syringe but didn't work. Looks like the other end of it is holding tight to some cheato? What's the best was to remove it?
Just toss that cheato, don't risk it. Also go to a craft store and buy a plastic needle point grid and try to put it in the cheato section so you can possibly quarantine this area from the display. Then keep an eye on the grid if you fine one dip the grid in water and scrub the spot you seen one of these basters. I still have them in my display but knock on wood their not bothering anything.
 
My return water from sump goes through a media bag before hitting the DT. Hope none of it gets through...

Do you guys know if cutting it kills it or splits it into 2 new bodies?
 
My return water from sump goes through a media bag before hitting the DT. Hope none of it gets through...

Do you guys know if cutting it kills it or splits it into 2 new bodies?
It does nothing, it comes right back. Glue works but applying glue under water is difficult. Toss all that cheato don't mess around.
 
Yea can't glue Cheato ;)

Tossing the cheato makes sense if that's the only one in the system (hope it's true).
 
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