Are These Small Leeches?

Are These Small Leeches?

Observation - Are These Small Leeches?. Description: I'm at something of a loss here. If they're not leeches I don't know what they are. There were a couple of black ones and a couple of brown ones. For scale, see the duckweed. I think they were 1 - 2cm in length. I offered them a finger, but they show

I'm at something of a loss here. If they're not leeches I don't know what they are. There were a couple of black ones and a couple of brown ones. For scale, see the duckweed. I think they were 1 - 2cm in length.
I offered them a finger, but they showed no interest.