Unusual tenant found, need id.

[rjs5134]

Practicing posting pics and hope someone can id this for me. It's been in the tank nearly a year now and appears from time to time. Very slow moving about 1"-1 1/2" in diameter. It looks like a flat disclike nudibranch.
http://www.reefland.com/forum/attach...1&d=1140973640

[BubbaWPB]

It's difficult to see the detail, but it looks like it has a single flat shell... that would take it out of the nudibranch group since they don't have shells. I'd guess its a Stomatella like snail, but that's only a guess.

[dragonladylea]

Bubbawpd - I'm with you if it has a flat shell its either a Stomatella or a Chiton and both are good critters for your tank. If it doesnt have a shell at all I would look into flatworms.

[rjs5134]

Guys,

Thanks for the quick reply. As I said, I only see it from time to time and it has never come to the front of the tank. I only had my camera phone to photo it so the picture sucks, but I don't think it has a shell. From what I can see, It's a flat-ish fleshy disk with a slightly raised bump down the middle. On the top of the raised area is a white stripe. The perimeter of the disk undulates like a sting-ray. Next time I see it, I will be certain to get a better shot, even if I have to buy a new digital camera.

[kevinpo]

Hard to tell from the picture but may also be a limpet. A search of the above types should bring a picture that you can ID.

Regards,
Kevin

[greenbean36191]

It's Scutus, a type of shield limpet. If you tap it on the back it will probably retract its mantle (the black fleshy part) and reveal the white shell underneath (which is the stripe down the back). They're relatively harmless grazers, but they will occasionally nibble on some sessile inverts like sponges, tunicates, and even some soft corals.

[mickey101]

I am new to salt water, only have had my tank since christmas 06. I have two of those black critters. I have some really good pictures but I must figure out how to post as this is the first time I have been on this site. I took the picture to my local dealer and he figures it is probably a chiton. They started out small and grew really quick. About 2" big now, and nocturnal.

[zhenya]

Hi mickey101,

I am new to salt water, only have had my tank since christmas 06. I have two of those black critters. I have some really good pictures but I must figure out how to post as this is the first time I have been on this site. I took the picture to my local dealer and he figures it is probably a chiton. They started out small and grew really quick. About 2" big now, and nocturnal.

The picture in the original post is of Scutus sp. , as greenbean had pointed out already. If you are talking about picture of your own critter that you observed in your tank, I highly doubt that Chitons can grow this rapidly.

Here's an abstract about the growth of Chitons from the article by Dr.Ron Shimek:


Growth has not been measured in tropical chitons, but in one common eastern Pacific species, Katharina tunicata, the growth rate appears to be about 1 millimeter (1/25th of an inch) per year. As Katharina may exceed 4 centimeters (1 1/2 inches) in length, it is reasonable to assume that the animals may live at least 40 years. This species likely becomes sexually mature at about 15 to 20 millimeters (6 to almost 8 inches) in length, so at about the age of 15 to 20 years.

You can find the rest of the article here.

So, after having said that, the point I'm trying to make is that you may need to investigate a bit further to determine what exactly you have. As far as uploading images, you can either make an attachment( look at the bottom of the window where you type your post and you'll see a button "manage attachments") or you can upload them into your gallery and include it in the text of your post. You can find a bit more about it here