Digitate Hydroids

Nikki will probably have better info on this but from my understanding Digitate Hydriods are somewhat common hitch hikers that will establish ground in a new tank. If you dont have any livestock simply starving them out will kill them off fairly quickly.

Colonial Hydriods on the other hand like to grow in colonies (hence the name) and can take over entire pieces of rock. Some people claim that covering them in kalk paste will kill them off while others have resorted to taking the rock out and boiling it.

Then again there are a number of things that look similar to hydroids that are harmless... if you have the chance to post a picture of the suspect hydriod that would greatly help with the recommended treatment....

I think you've covered what all I'd say! :)



This is what they look like not all stretched out (usually they hide in the rocks and stretch out...so this is an unusual shot). I have a video of it somewhere...it's crazy to watch!

I don't recommend them in seahorse tanks, but I've never had an issue with them in a reef tank (granted, I still don't like them and don't have any currently). If you don't like them, you can put a dab of superglue, kalk-paste, or epoxy over their hole when they retract.

Yeah i agree with Nikki, unless your raising fry or keeping seahorse(s), dwarves especially, i wouldnt even be concerned with hydroids.