red tiny snails floating in my SPS tank? I.D. please.

[Reef_Newbie]

Hello All at ReefCentral,

A few days ago I noticed that there were quite a few of red dots floating in my tank. I put a net at the outlet and caught 7-10 each day. I took one out of the net and took pictures of it to post on this thread, so experts on reefcentral can help ID it. Initially, I thought these might be red bugs. But when looking through a 10x loupe, I found that it's much like a snail with two eyes sticking up and a long soft body - just like the ones you find on your lawn but much much smaller and with different color. Please look at the pictures and give me advise if I should be concerned. The last pic is the size of that creature compared with a penny coin.

Thanks,
Reef_Newbie

ps. The last frag I added to the tank was a digitata on 11/28/11 which I dipped in Revive for over 10 minutes. Worms, pods, and bugs wiggled out and died, but I didn't see any snails falling off from it (didn't see any on the digi either). The prior frags were added over a month ago, and they were dipped on Revive as well. Same result, pods, bugs, and worms fell off and died, but no snails detected.

[TreyK]

They are flatworms

[Reef_Newbie]

Thanks TreyK. I searched but couldn't find the pictures of these anywhere, so I thought they were snails :P

Is this type of flatwarm a threat to corals? They didn't seem to bother any acropora or monti in my tank... yet...

Thanks.

[TreyK]

Not sure, Ive never really researched them because Ive never had an issue with them. The most I could imagine them doing is smothering corals if they reach plague like proportions. I would do your best to eliminate them now, I imagine they reproduce rather quickly.

[pcfish]

Red Planaria flat worms they are harmless but can get out of control. Wrasses will eat them. You can also treat with salifert flat worm exit but be careful. Do some searches on RC ad read up on it. There are some horror stories.

[Tomoko Schum]

I don't think it's a red planaria. The common red planaria is much smaller than the creature in the picture. It looks more like some sort of seaslug or nudibranch to me. It's hard to say whether it is harmful to corals or not without knowing what it is. Some of nudibranch look like what it eats.

[dzhuo]

These are not red planaria or flatworm in general. It's a common nudibranch (Oxynoe sp.) that occasionally shows up in our reef tank. They are not harmful.

[Reef_Newbie]

Thanks to all for the replies.

I took a few more out for inspection, and all of them have eyes sticking out and there seems to be something building up on their back (please see additional photos). At this point, from looking at tons photos on the internet, they look more like baby sea slugs than flatworms. I googled Oxynoe sp. per dzhuo's comment, and these animals floating in my tank might be their babies :D

I am thinking about raising them in an isolated tank into adult size. I am curious how they look like when they grow up.

So far, they are harmless to both corals and fishes, and they don't seem to be delicious, either. Clown fish and demsel don't even eat them when they flow by.

[Rockys_Pride]

The trick is finding their diet. Nudis, for the most part, follow a strict diet. Not that they don't want to eat, but are very specialized.