Live Rock Hitchhiker Id's

[PaperArrow]

Hallo everyone, I have noticed a few hitchhikers on the live rock I got yesterday, mostly feather duster worms, and pods, but I have noticed two of these tiny little critters, the orange one is the larger of the two, about 5mm, it moves and looks like a spikey slug, it has four antenna two front facing and 2 upward, and about 12 spikes, the white one is smaller about 3mm, with darker spikes, I have uploaded some pictures and a video, the video should be much more helpful, if anybody can help me Id these things that would be great, they are not shy they have been out in the light all day, I would very much like to read more about them.

The smaller white one.....

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[Ricey]

a type of Nudibranch.. not sure which though?
I think they are generaly reef safe and are algae eaters.

EDIT: just read that they are grazing carnivores and as a whole they feed on a wide variety of animals including sponges, hydroids, tunicates, anemones, corals, sea pens, bryozoans, barnacles, and sometimes other nudibranchs! so it would appear not to be reef safe at all!

 

[SkiFletch]

Nudibranch definitely. Nudibranchs are obligate predators of a specific organism. Could be anything from a species of algae, to sponges/tunicates, or as nefarious as zooanthids. The latter looks to me like what you have pictured. Zooanthid eating nudibranchs obviously eat zoos and take on the color of the zoos that they eat. They grow fast and can wipe out a tank of its zooanthids very quickly. Take notice of where your nudis spend their time, because they typically stay on top of thier food source. In the absence of their prey, nudibranchs will perish, so if I were you I'd just keep an eye on them and see what they do. If you do have zoo-eating nudis and have no zooanthids in the tank, they wont live for too long.

DO NOT, I repeat, DO NOT under any circumstances touch ANY unknown nudibranch with any of your bare skin. Nudibranchs concentrate the poison/toxins of their prey in their own tissues as a mechanism of self defense. While a zooanthid does not have enough palyotoxin in itself to be harmful to humans, a zoo-eating nudi which has eaten whole colonies and concentrated all the palyotoxin of the entire colony into its own tiny body can cause an aquarist whose made contact with them to have as mild a reaction of a rash to as severe a reaction as anaphylactic shock. There is no known cure for many of the toxins that nudibranchs use for defense, so take care. Read this to hear what happened to someone who squished a zooanthid eating nudi with his fingers...

Many can be harmless algae eaters, and many can be dangerous. Adopt a wait and see approach to figure out what yours are up to.

 

[PaperArrow]

Thanks very much, definitely a nudibranch, not as nice as the one in the picture.
its a shame as i quite like the little fella, it being the first hitchhiker and all
so it would be best to get them out now before i loose them?

 

[SkiFletch]

Thanks very much, definatley a nudibranch, not as nice as the one in the picture.
its a shame as i quite like the little fella, it being the first hitchhiker and all
so it would be best to get them out now before i loose them?

Read my post above, looks like we did so simultaneously. Leave it for now as your tank is still new. If it does prey on a specific type of sponge, tunicate, or other invert, it will exhaust its food supply and perish. Better to let it run its course than mess with it when you dont know what its eating.

 

[PaperArrow]

PHEW! that was close! Thanks for the heads up. imagine hospital on day one.
So the brown coloured one is likely to be the problem, it spends all its time on one rock, no zoos on their as it is a new tank, but the rock came from the coral display tank so it could have been under any coral anemones etc...

The white grey one has spent the whole day up and down the glass so i don’t know what he is after......dazed in the new surroundings perhaps?.

 

[SkiFletch]

PHEW! that was close! Thanks for the heads up. imagine hospital on day one.
So the brown coloured one is likely to be the problem, it spends all its time on one rock, no zoos on their as it is a new tank, but the rock came from the coral display tank so it could have been under any coral anemones etc...

The white grey one has spent the whole day up and down the glass so i don’t know what he is after......dazed in the new surroundings perhaps?.

Yeah probably not sure where to look for prey. If it came from a display tank at your LFS, they could be anything. Just let em hang around while you're cycling