Is this a flatworm

[Raj]

I saw two of these after light went off on my tank

 

Is this a flatworm ?? Is it bad for my tank ??

It was on one of my live rock

 

 

 

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[Jon Lazar]

It looks more like a nudibranch to me.  I wouldn't worry about it.  I wouldn't add it to my tank on purpose, but I also wouldn't tear things apart to remove it.

[mari.harutunian]

Do you know if it has a shell underneath? Could be a cowrie.

 

 

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[Squishie89]

Looks like a type of limpet to me, maybe a keyhole or elephant

 

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[GraffitiSpotCorals]

Yes it looks like a flatworm. You can baster it off the rock with a turkey baster most likely, unless it's really large. Most large ones like that I have seen are the type that eat snails.

 

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[Raj]

They were next to crabs but won't seem to be feasting over corals but left over fish food I'll try to take some more pictures soon

 

 

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[Raj]

Do you know if it has a shell underneath? Could be a cowrie.

 

 

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No shell underneath it's all fleshy like a snail

 

 

 

 

 

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[sethsolomon]

I am 90% sure it is a Dendrodoris nigra.  They eat those black encrusting sponges we sometimes get in our reef tanks.

 

Image of the sponge: 

[Raj]

I am 90% sure it is a Dendrodoris nigra.  They eat those black encrusting sponges we sometimes get in our reef tanks.

 

Image of the sponge: 

 

 

I do sometime get that Sponge on my display tank... I think you are right.. I will just leave it do its thing ...

 

Thank you all for sharing your knowledge!

Edited July 10, 2017 by Raj