Hey

I've just found something weird in my tank.

I got some corals a few months back and one of them hasn't been doing too well. Anyway, a few times over the months I've noticed that this coral goes purpleish, sweels slightly and then seems to push out this white kinda pus. This generally disapears and then the coral is fine.

So, I looked this afternoon and it's happened again. Me and the hubby have just looked in the tank again and the white stuff is identical to the coral but in minature and white, not pink. It also seems to be 'walking' across some seaweed at a rate of about 1" per 5 minutes.

Is this breeding? Or is it something to worry about?

OK, it's not any kind of coral. On closer inspection it appears to be some kind of sea slug. It's white, has 'feathers' all along its back and is about 1.5" long. Hubby is getting a pic as we speak...could somebody shift this to the ID forum?

Right, Google images is saying it's a nudi...why it's only just decided to appear now (especially as I've just dismantled and put back togoether after a new floor!) I don't know. Any clues on how it'll work in there?

Nudibranch are a type of sea slug and are common in the sea and occasionally hitch hike in live rock or on corals. There are different types and while some are pest control or vegetarian algae eaters many others like corals, sponges and even other Nudibranch.
Fascinating creatures.