Enormous “algae eating shrimp”!!!

[Clare]

Hello, not sure where to post this, so “algae” seemed as good a spot as any where…

I have some shrimp who have grown ENORMOUS and am wondering what they are! Up until now I thought they were North Queensland Algae Eaters, but have just realised NQ shrimp don’t grow to anywhere near this size!

To help combat Algae I have made some bulk purchases (NQ shrimp, glass shrimp, “mixed” cherry shrimp)…and it seems there must have been some stowaways!

These things are atleast 5-6 cm long, with one massive claw!! I thought they were cool, but now that I realise I don’t know what they are, I’m a bit freaked out!!

Does anyone know what sort of shrimp these are? And if so, are they ok to keep in my tank?!

 

[GreggZ]

Looks like a crayfish not a shrimp. Maybe the Australian Redclaw Crayfish (Cherax quadricarinatus)?

If so going to get a lot bigger and will likely eat anything that moves in the tank.

 

[Clare]

Hmmm.

a. Yikes!
b. Don’t seem to have the same colouring. Mostly mottled brown, with a white stripe near the rump. Will try and post more photos…..

 

[BryceM]

Those critters would NOT be welcome in any of my aquariums. They'll each anything they can catch.