What is this? Worm? Hydroid?

[reddevilant]

Hello. So a month ago I got some macro algae and one of them had some hitchhikers (bristleworms, large amphipods) so instead of putting it in my main display, I put it in my 40g tank. It’s been a month and I only just noticed these little things attached to the glass and eggcrate in the tank. The tank was ment to be a grow out tank for macros but any that I’ve put in there hasn’t done too well. So basically it’s just been a holding/short term observation tank for macros and home to a single converted molly.

Anyone know what this is? Is it something that will release toxins if it dies? They’re tiny but there’s a lot of them. I’m planning on using this tank as a quarantine tank for new fish this summer. But, I don’t want to crash the tank if copper kills these things and they release toxins. Thank you for any info you’re able to provide!

 

[fishface NJ]

ball anemone

 

[shakacuz]

does seem like a hydroid. if it stays that small it definitely is. if not, it could be a ball anemone

 

[reddevilant]

ball anemone

does seem like a hydroid. if it stays that small it definitely is. if not, it could be a ball anemone

I actually first noticed them last week and they've stayed that size so far. The one in the picture is the largest I saw. Are either of those, ball anemone or hydroid, dangerous?

 

[fishface NJ]

No not dangerous

 

[reddevilant]

No not dangerous

Ok thanks! Is there an easy way to get rid of them? I'd like to use that tank as a quarantine tank and treat new fish with copper. Should I try to get rid of them first or would it be ok if I got new fish, treated with copper, and the ball anemones died during quarantine?

 

[WheatToast]

I have had these cnidarians pop up once in my temperate system, though I never figured out exactly what they were. They showed up all over the tank, lasted for a few weeks, and then all died out without a trace. Their only tankmates were macroalgae and microinvertebrates, so I do not know what impact they would have on corals and fish.

 

[reddevilant]

I have had these cnidarians pop up once in my temperate system, though I never figured out exactly what they were. They showed up all over the tank, lasted for a few weeks, and then all died out without a trace. Their only tankmates were macroalgae and microinvertebrates, so I do not know what impact they would have on corals and fish.

Ok, thanks! I just want to try and make sure they won't release anything when they die from the copper. I believe they came from the Flamingo Feather algae I got from Tropical Fish Plus because that's the only thing that has been added to the tank in the last month or two. I think I remember you posting on your build thread that you had found some hitchhikers on an order from them a while ago.