Shed or dead ?

What you reckon, is this a shed or a dead hitchhiker ?

 

Hi Warr - most likely a shed. Those hitchhiker crabs are EXTREMELY strong. They can stay inside live rock that was lying outside of water, for at least a week or so without dying....

 

How do these crabs actually hurt our systems?

 

Many crabs are quite reefsafe - but as they get larger they can be clumsy and knock our rock work over - and are only algae grazers.

Some crabs start off ok, but then become opportunistic and take snails/hermits etc

And there are some species of crab which are just out and out carnivores and will go for small fish, or even larger sleeping fish.

But we do need to remember, they didn't ask to end up in our tanks, they went to sleep in their hidey hole one night and woke up in a glass box mant thousands of miles from where they started, so remember we also owe them a duty of care, sump them of return them to the shop, but don't just kill them because they have eaten something that cost you money.

 

LappiesReef - these crabs always seems to end up killing some invertebrates. In my case. It called all the starfish I had in my tank. Even my last starfish (which I had for about 8 months). When these crabs become bigger, they could start attacking sleeping fish.

 

I see. Thanks guys...

I like your approach Wee-Man. I fully agree...