Digitate Hydroids spreading fast and getting very long

b4tn · Jan 29, 2020

I dont know where these things came from. I recently moved houses and decided to do a tank reboot, bleached my rock, and started over with the frags from my old reef. So technically its only about 4 months old. I have added some new frags over the past couple months but I first noticed these hydroids in a patch of zoas from my old tank and they have since spread all over. I have done some research and I cannot find a lot of info on them. Some say they sting, some say they dont, some say they go away, and some say they will over take a tank. lol. Mine in particular did not seem to bother anything until recently. I have some that are near 4 inches long sweeping around at night and appear to be bothering my stylo and the acro in my profile pic. It went from growing like mad with lots of PE to all of sudden no PE and getting pale. I took a look one night and saw one of these hydroids flopping all over and around the acro. I am going to move it tonight and see if it recovers but how can I get rid of these things? They only come out at night and appear to come directly out of the rock. Manual removal I think would be impossible. I do feed coral frenzy every day but its part of my routine to keep N and P from bottoming out. This is not my pic I stole it from another thread but identical to mine.

ihavecrabs · Jan 29, 2020

Maybe try dosing nitrate and phosphorus and not feeding coral frenzy. You may find that the food particles are feeding their growth and larger population.

Jman76 · Jan 29, 2020

I went thru this problem a few months ago. They absolutely irritate coral. Info is indeed vague. This is what worked for me: I basically stopped all broadcast feeding, especially the ReefRoids and ReefEnergy A/B, just target the fish. I wouldnt quite call it tank starving, but you have to reduce their food source drastically. They will thin out and eventually disappear. With the rate mine were multiplying, I thought they were gonna wipe evrything out. Patience will prevail! Also, I found that some of the ones really close to coral, I could put a dot of F-Aiptasia or superglue over them(not practical to try and get them all). Good luck

b4tn · Jan 29, 2020

Kind of a pain but I could stop broadcast feeding coral frenzy and turn the scrubber down more and see if that helps. I think one of the hard parts is I can’t tell where they come from. I don’t see a tube or anything they are just come out of the rock and are light sensitive so if I shine a light on it they suck back in to where ever they come from.