I have no idea what they are SBG but I'm commenting coz I'd love to know!

They look like leaches to me. Yuk! Take them back to the gc and tell them they can keep them!

Oh gosh Seaburn, I do hope you weren't charged extra for the livestock, I'm never sure about which ones are the friends in our gardens, I have a vague recollection of a member saying which ones did no harm in the gardens but cannot for the life of me remember who it was, hopefully you'll get an answer and we'll all know.........

The first one looks suspiciously like a New Zealand Flatworm to me.
The second is a bit hard to see really.

NZ Flatworms are just that, very flat and the top one seems to be rounded. I thought it was a slug at first but it could be a leach or something completely different! I think that the bottom one is an egg case and may potentially contain hundreds more of the top ones!!!!!!!

When I saw your question and before I saw the photo my thought was 'New Zealand flatworm' but, as Bulba says, they really are flat and don't contract and stretch.

the second one is a view of the underside of the first one, through the glass.
they are very flat and leeches have clear rings of body segments and these don't have any obvious segments.
they are definitely flat worms but which ones? Their movement can be a gliding motion like a slug or more contractile like a worm.

They are both alive and well in the jar this morning.
Googling images of nz flatworms does throw up images like these critters. But try googling british flatworms and you get lots of images of the nz one.

I have sent pictures off to the RHS help line and to NHM to see what they suggest. I just thought I'd see if anyone on here has had anything like them in their experience.

But they are definitely not slugs nor a true worm which is segmented such as leeches and earthworms.

I'll keep you posted.

Put a small earthworm in with it, if it eats it then it is a NZ flatworm.

You could email Defra too....or Fera the research people
Ifs that the head end it does look leechish.....
Will watch thnis with interest Seaburn.

just a comment to find out what it is

They're leeches. Harmless. Pop them back into the pond.

The rule always used to be ' If they move quickly they are the gardener's friend. If they move slowly or not at all they are enemies.'

well they are NZ flatworms. I have a contact at the NHM who is re-cataloguing many of the invert species and he kindly id'd them for me.

the pictures also match the defra info sheet. they are now dead flatworms.
Leeches have clearly body segments Worthy as they belong to the Class Annelida, the true worms.

Do you think they were imported with the plants?
Maybe you should contact the nursery where the plant came from Seaburn?

sorry that should say Phylum Annelida, Class Hirudinia re the leeches.

I did ring the nursery when I first found them and he said they were skinny slugs and he doesnt import plants from New Zealand!

Oh........

Present the nursery with the defra information sheet. Skinny slugs indeed!

N Z flatworm isn't just in New Zealand, we have it in our village!

The RHS have replied and also say NZ flatworm. I don't think I will be using that nursery again.

Try reporting them to DEFRA

Sbg, I stand corrected. I've looked more closely and I can see they're not as evenly shaped as leeches. Apologies. And I was born in Auckland!

Defra's site says there is no need to report them as they are very widespread.

Yes they are - far more widely than most folk realise! Thankfully our native earthworms seem to be withstanding their attacks.