Unknown critter, maybe isopod, ID needed please?

[ZzyzxRiver]

I’ve never seen these before. I’m assuming they came in on my last purchase about a month ago. The rock my Yuma was on had been sitting in the sand bed while I figured out where to put it. When I moved it, I noticed these. Are they a problem?

@ISpeakForTheSeas

 

[Mebbid]

Looks like a Chiton to me which would be an algae grazer. Poke it, is it hard or soft?

 

[ZzyzxRiver]

You know, when I went back to look at them again a few minutes later, they were all already missing. Chitons don’t move that fast, do they?

 

[Mebbid]

You know, when I went back to look at them again a few minutes later, they were all already missing. Chitons don’t move that fast, do they?

According to google top speed of a chiton is 21 inches per hour. 3 inches in 10 minutes is enough to go missing

 

[ZzyzxRiver]

Hopefully they are harmless/helpful and I get to see them again sometime!

 

[ISpeakForTheSeas]

I’ve never seen these before. I’m assuming they came in on my last purchase about a month ago. The rock my Yuma was on had been sitting in the sand bed while I figured out where to put it. When I moved it, I noticed these. Are they a problem?

@ISpeakForTheSeas

I can't tell from the pics if these are flat or have things (like bristles or cerata) sticking off them. If flat, then chitons are a solid possibility; if they have things sticking off, then I would need to know what to give a proper ID, but a slug (like a nudibranch) or a polychaete would be the most common.

 

[ZzyzxRiver]

I can't tell from the pics if these are flat or have things (like bristles or cerata) sticking off them. If flat, then chitons are a solid possibility; if they have things sticking off, then I would need to know what to give a proper ID, but a slug (like a nudibranch) or a polychaete would be the most common.

They were flat!

 

[ISpeakForTheSeas]

They were flat!

Yeah, then chitons would be my first thought too. These would have eight overlapping plates on their dorsal side (their top/back) that look like a rolypoly.

 

[IceNein]

If they're chitons, depending on the species, you may rarely see them. I have two pretty large chitons that always hang out grazing the rocks, below the sand line. Sometimes I see them on the glass under the sand.

 

[ZzyzxRiver]

If they're chitons, depending on the species, you may rarely see them. I have two pretty large chitons that always hang out grazing the rocks, below the sand line. Sometimes I see them on the glass under the sand.

I never saw them until I moved the rock, so that sounds right. I hope I have more!