ID what is this?

[dnsfpl]

good or bad?

saw a few together with my bag of shrimps

[lucasjiang]

A wild guess... its a water boatman i think

[Navanod]

Looks like a water boatman. If it's swimming upside down, it may be the more dangerous kind.

[dnsfpl]

so is consider a bad pest in shrimp tank?

lucky i never pour everything in

thanks both

[Navanod]

It's not welcomed in a shrimp tank that's for sure. The upright swimming one is mostly a plant sap drinker if I'm not mistaken. But the upside down swimming one is a hunter, that's why it needs to have its eyes underwater, to be able to see and catch preys.
Get rid of them as much as you can, they are certainly not goods to have

[dnsfpl]

thanks for the info

[shrimpster]

I dont really put any other animal inside shrimp tank ... it seems for the they like to be exclusive :P