Just curious if baby (not sure on technical term for "baby" shrimp) peppermint shrimp go through a larval stage or if they hatch as fully formed "mini" shrimp?

I have recently noticed in my fuge a lot of very small shrimp like critters (they look identical to the baby cherry shrimp I get in my FW tank). They are most likey just a new form of 'pod I hadn't seen/noticed before but I have only seen them since I got my peppermint shrimp so was just curious if it could be baby peppermint shrimp or not.

I tried to take photos but being only 3-5mm big and moving very fast its next to impposible to get a good photo of them. I noticed them about 2 weeks ago when they where a lot smaller and they seem to have got queit a bit bigger and darker coloured then when I first noticed them. the peppermint shrimp spend quite a lot of time in the back compartments of my tank as well (where the pump to the fuge is) so it is possible eggs and/or baby shrimp got sucked up into the fuge (they are mostly concentrated in the first compartment in the fuge which also makes me believe they got there from the main tank).

They sound like mysid shrimp. Peppermint shrimp larvae are funny looking things that do not resemble their parents. They float about in the water column for a month or so before settling and metamorphosing. Then they look like miniature peppermint shrimp. The larvae are weak swimmers and would be unable to swim around a sump with reasonable water movement.

Thanks Colin, I thought that would be the case but wasn't sure just a coincidence that they turned up shortly after the peppermint shrimp. Got to say this is the coolest thing about marine tanks, 8 months on and I'm dtill seeing new stuff coming out of nowhere

yep marine tanks are great in that respect. The longer they are set up the more things appear in them, especially if you use natural seawater.