Tunicates: Bane or boon? ...or neither?

[Bill The Cat]

I've got a fairly new reef tank (four months) going, and I'm still in the process of stocking it. This is my first foray into the reef arena, but I kept a remarkably healthy f/o setup for about six years back in the early 90's before stepping away from the hobby until just recently.

One of the live rocks I have in my tank came in with some kind of Tunicate on it; as yet unidentified. Initially, I thought it was a sponge, but realized that couldn't be the case, as there were several points during transit and setup when the rock was exposed to air for prolonged periods of time; a sponge would have likely kicked off as a result of that. On the other hand, this Tunicate seems to have snapped back nicely, and possibly even propagated a bit.

Does anyone have any experience with Tunicates? Should I attempt to pull them out for fear of outcompeting the corals, or are they okay? I realize the answer to a question like this often depends on the animals involved: For now, all I've got coral-wise is a small colony of Rhodactis mushrooms, but I'm looking to add some Xenia, an Anchor, some Frogspawn, and a Sarcophyton. I haven't been able to ID the Tunicate yet, but it looks like a small creamy yellow ball; its tunic is very translucent, allowing you to make out the honeycomb pattern of its inner plumbing. The initial specimen started off slightly larger than a nickel, but is currently about the size of a quarter; at least nine others popped up in the last month, and those range from the size of a tailor's pinhead to the diameter of a pencil eraser.

[Ninong]

Tunicates rarely survive longer than a few months at the most in home reef aquariums.

[kevinpo]

Hello,
They sound like colonial tunicates that are common in newer tanks. They will not harm corals or fish. In most reef environments they fade away in about a year. The type I think you are referring to don't like high light but reside in shaded areas of moderate to high flow.

Regarding sponges, there are many that can be exposed to air and survive. Several common species are rather hard to kill and can become a problem in a reef especially the coral skeleton boring type.

Regards,
Kevin