Does anyone know what this organism is. I love these and has only shown up in my established tanks. They are small red stalked coralline like organism

[Ron Primas]

I would treat them as filter feeders, kind of. They'll capture particulate matter, food, bacteria, etc. So, if you have a healthy tank and they can source food, they'll remain in your tank. Their numbers might ebb and flow, but they should stick around for the most part. You'll probably find them in shaded areas or where flow passes by, where they can capture food. In my 15g I had set up in the 90's, I had a great deal of them in the tank and in my 10g display refugium, some of which were rather large and could be mistaken as coral. I had some really cool pics of them (and my tanks) but lost them when we moved to SoCal.
Sometimes you'll get lucky and they'll hitch a ride on frags and certain corals, as mentioned earlier. But if you were keeping reef tanks before live rock disappeared, then you most likely had these cool critters in your tank.

Sorry for the delayed response. I really appreciate all of your knowledge!!!

 

[mindme]

Lucky you. I had some on a rock a long time ago and never since. They are really cool.