Christmas tree work rock has a strange animal attached to it.

[Spiderwoman]

These 2 open mouths are in the base if a Christmas Tree Worm rock and they close when food goes in. I’ve never a seen this kind of animal before. Any idea what they are?

 

[TDEcoral]

Looks like a tunicate.

 

[Tired]

Yeah, tunicate. It's a harmless filter-feeder.

 

[Spiderwoman]

Thanks guys! For months I thought there was something wrong with my eyes when I'd be looking at the rock and would think that something moved in the corner of my eye. Today it happened right as I was watching and saw the mouth open, grab the food and then close Coolest thing!

 

[shred5]

Sea squirt.

 

[Tired]

Wanna know something cool about tunicates/sea squirts? They're chordates. Chordates are the group of animals including all animals which have a notochord at some point in their life. A notochord is a simple backbone. The animals in chordates are sea squirts, a weird little thing like a boneless fish called a lancet, and... vertebrates.

Those little guys are your closest non-vertebrate relatives.

They don't always do great in aquariums, because they're filter-feeders. Smaller ones usually do better. If whoever buys it gives the tunicate the same foods they give the Christmas tree worms, that should improve survival odds.

 

[Spiderwoman]

Wanna know something cool about tunicates/sea squirts? They're chordates. Chordates are the group of animals including all animals which have a notochord at some point in their life. A notochord is a simple backbone. The animals in chordates are sea squirts, a weird little thing like a boneless fish called a lancet, and... vertebrates.

Those little guys are your closest non-vertebrate relatives.

They don't always do great in aquariums, because they're filter-feeders. Smaller ones usually do better. If whoever buys it gives the tunicate the same foods they give the Christmas tree worms, that should improve survival odds.

That's the coolest thing! This rock has been doing well, I have it in the bottom with a good flow, the worms are thriving, and I've seen a few new babies show up. All 4 Paguritta harmsi crabs are doing well and they're fun to watch as they grab food from the water column. The Porites coral isn't do so well, the lighting in the bottom is not quite enough for it and I'm hoping it recovers as new lights go up possibly next week. The rock is currently in 26 inches of water under Red Sea ReefLED 90's which doesn't give quite enough PAR that deep in, but we're coming up with a new setup in a floating canopy with the existing 4x ReefLED's and adding 3x Radion XR15Pro Gen 5's. That should give enough light.