I had this in my tank early on so I thought I would share it here for reference. Let us know if you have them or hanve had them. In my experience i had one that I thought was cute and interesting. Then I had 3 a few days later and then like eleventy billion. I just did carbon and water changes and they eventually petered out and went away (I did smash like half an eleventybillion with a chopstick). They care certainly unique little organisms, but they allegedly sting coral and/or fish. Who's had these?