Alien life form in my tank

[Rob F.]

I have been battling an Algae issue in my fish only saltwater tank for some time now. I came across a video from Marine Depot on setting up a Algae reactor with Chaetomorpha Macro Algea and a led light strip rapped around the reactor. It’s up and running with a GFO ractor. That was almost a 2 months ago and the tank looks great. I was able to combat my algae problems in the tank. Now as of a few days ago I noticed these little white dots on the glass. While making a closer inspection they seem to be some kind of plant similar to an anemone of some sort and they are multiplying on the glass. Went to the pet store to show them some pictures and a video and they were clueless. So I made a decision to order some Copper to dose the tank hoping to kill whatever it is in my tank.

I'm hoping that someone will be able to recognize these weird pest in my tank. Also I had the same fish in the tank for over 5 years now and haven’t added any additional fish to the tank since.

 

[Supurderek]

It's a type of hydroid. Tends to go come and go. Harmless. May be triggered with change of filtration.

 

[lambchops]

Do you have a fish only system? I wouldn't dose copper either way, but definitely don't if you have inverts.

 

[sa6hir]

I had these in my tank when I set it up new, I just scraped them off never to be seen again, that was about 6-7 months ago.

 

[Rob F.]

thanks everyone for replying. This is a fish only tank with no inverts. I tried to scrape them off the tank but seems to come back stronger.

 

[Lionfish Lair]

They are called medusa hydroids, which is a stage in their life cycle, not a type/species. As said, they will go away in a bit. Please don't treat your tank with copper for the sake of getting rid of these guys. It's honestly not necessary.