What is this on my filter sock???

[Bundem]

Hi I have recently set up a Tropical aquarium, which includes a sump with filter sock filtration and after 3 months of having a successful tank I noticed this little alien on the outside of my filter sock. Does anyone have any idea what it is, I cannot seem to find anything on the internet. It is about 15mm in length.

Also, is it dangerous or going to be a problem?

Thanks in advance.

 

[Slaphppy7]

Dragonfly or damselfly nymph.
Predators of small fish, dispose of it.

 

[Rocky998]

Have fun catching it lol... I had one in my tank and it took a little more than a week to finally catch. Their very tricky

 

[Bundem]

Thanks for the fast replies. Hopefully I can get it out, definitely is going to be a task. I bet there will be more than one too...

 

[itiwhetu]

dragonfly Lavea not great in your tank try to catch it