Planaria - Good or Bad?

[CozyCat]

Hi,

Found this guy crawling around the substrate up against the glass in my planted aquarium this morning. Pretty sure it is a planarian. I caught it and put it in a small container, I also put a snail in to see what it does and it has eaten the snail

What do people think about them? Are they good or bad for the aquarium? Should I invest in a trap to remove them?
I have noticed the snail population declining in recent weeks, I don't mind too much since there were a lot of pest snails.
I do have shrimp in this aquarium though, are planaria harmful to shrimp?

Thanks in advance for your thoughts

 

[Colin_T]

That's one big planaria if it is one. I would say it might be something else, but if it eats snails and you hate snails, leave it in the tank until the snails are gone, then kill it.