What is this alien? Tunicate?

[reddevilant]

I recently added some macro algae to my tank that came in already attached to a rock.....or at least what I thought was a rock. I had noticed the “rock” was softer, almost sponge like. I have other macros whose holdfast structures had similar textures so I figured that’s what I was feeling attached to an actual rock. But, to my surprise this morning when I was checking the macro out, the rock had two red tubes/mouths? (One of which is not visible in the pic I’ll attach but is identical) with what almost looks like 3-4 white teeth around the opening. I don’t believe they are pores of a sponge because when disturbed or spooked by a nearby fish, it would completely retract the tubes and cover up to look like a normal rock (which I’ll try to get a video of later). I’m not really familiar with tunicates so could this be one? Is it safe to keep? Thanks for any and all advice/information!

 

[Mr_Knightley]

Definitely a tunicate! If the whole rock feels squishy, then that's a big tunicate! I may need supplemental feeding to survive long term. Or it may defy the laws of nature and live for years. Nevertheless, super cool.

 

[reddevilant]

Definitely a tunicate! If the whole rock feels squishy, then that's a big tunicate! I may need supplemental feeding to survive long term. Or it may defy the laws of nature and live for years. Nevertheless, super cool.

Awesome! Do you know what they eat? Phyto? My tank has been up for over a year and I've had pretty good sponge growth of a couple species even before regularly dosing phyto. So I assume my tank is at least somewhat well established for filter feeders.

 

[DaJMasta]

It depends on the species, but I'll bet most can eat phyto. I've had them survive in tanks without phyto dosing, so finer particulate foods are probably sufficient to keep a lot of species going too. These larger variety seem to stick around better than the small colonial species, though I don't think I've started dosing phyto early enough after adding live rock to really give the colonial ones a fair shake.

 

[reddevilant]

It depends on the species, but I'll bet most can eat phyto. I've had them survive in tanks without phyto dosing, so finer particulate foods are probably sufficient to keep a lot of species going too. These larger variety seem to stick around better than the small colonial species, though I don't think I've started dosing phyto early enough after adding live rock to really give the colonial ones a fair shake.

Ok, thanks for the info! If this one lives for a while maybe I'll look into getting some others. Preferably ones that don't look like a sci-fi monster. Those little white, teeth-looking protrusions really freak me out lol.

 

[Peter Houde]

I recently added some macro algae to my tank that came in already attached to a rock.....or at least what I thought was a rock. I had noticed the “rock” was softer, almost sponge like. I have other macros whose holdfast structures had similar textures so I figured that’s what I was feeling attached to an actual rock. But, to my surprise this morning when I was checking the macro out, the rock had two red tubes/mouths? (One of which is not visible in the pic I’ll attach but is identical) with what almost looks like 3-4 white teeth around the opening. I don’t believe they are pores of a sponge because when disturbed or spooked by a nearby fish, it would completely retract the tubes and cover up to look like a normal rock (which I’ll try to get a video of later). I’m not really familiar with tunicates so could this be one? Is it safe to keep? Thanks for any and all advice/information!

Sorry to disagree, but it doesn't look like the body plan of a tunicate to me. I found (an apparently dead) one of these as hitch-hiking on some Gracillaria I recently bought. Put it under a microscope. At least the one I examined didn't have any of the requisite body parts of a tunicate.