Does anyone know what this is?

[Aiken Drum]

Does anyone know what this woodlouse like creature is i found after some tank maintenance. About 6 or 7mm long. Never seen anything like it before. Where might it have come from? Am i likely to find more? Will they cause any harm?

I took it out of the tank.

 

[rlederer]

It could be an aquatic louse.

 

[DrWho42]

it might be a louse?

 

[Aiken Drum]

Ive decided that it looks like a woodlouse because it is a woodlouse. Finding them all over the carpet this morning. Must have somehow got in the tank while the lid was off doing tank maintenance.