Another ID thread... mini feather dusters?

[ToddTT]

What are these little things above Bob's head?

They have been in my tank for 8 years or so. Never seem to change size much, but tend to pop up here and there, including on base rock that was in the tank before the live rock was introduced.

[ricksreef]

Looks like digitate hydroids to me and they can sting just about any coral placed near them
and can spread rapidly when/where your not looking.

[ToddTT]

Can they also sting fish and snails?

I currently have just a few patches of these in my FOWLR 75 gallon.

Should I continue to ignore them, or try to remove them?

[returnofsid]

I agree, they look like colonial hydroids. Yes, they can sting and irritate. They're a pain in the butt!!

[ToddTT]

Yep, hydroids. Thanks guys.


Lots of hydroid victims out there:

aquariofilia marinha - REEFFORUM

HydrozoanFAQs

Xtalreef

get rid of hydroids - Google Search


I can't find any foolproof or reliable solutions for getting rid of these. Seems like there are some hard-to-find nudibranches that eat them:

The Sea Slug Forum - Pteraeolidia ianthina



And sometimes angelfish will eat them, but it's hit or miss.

I may add a dwarf angel, or a Potter's angel. That was a plan before I even realized I had these bad hydroids in my tank.

Tweezing and siphoning during water changes is another suggestion, with varying degrees of success reported by people.

I'm wondering if I should invest in a powerful canister filter to use like a vacuum, so I can pluck and vacuum these damn things anytime I spot one?

Any suggestions for a canister filter that is powerful, easy to maintain, and easy to prime? That would act like a vacuum?

I was looking at these as a possibility:

Aquarium Pharmaceuticals RENA FilStar Canister Filter



Any other suggestions, like DIY vacuums or something similar?

I want to get these out of my system before they can inflict any damage on my fish! I bet there have been times where this or that fish was acting a little weird or stressed because he had just gotten stung!

[TimH07]

i have these and the best way to kill them is to take a 5ml syringe from a test kit with the needle end and get some ro water boiling and just spray them, over and over and over and over, day after day after day.

if you cook them and wait a few days the colony will repopulate.

keep at it.

also i have montipora cap. growing over these so they wont sting every coral out there.