Mosquito larvae

hey guys,

Every so often I set up a mosquito culture outside by filling a bucket with
water and some leaf litter and just waiting. Pretty soon there are wrigglers
that I catch and give to my fish (cichlids/tropicals/bettas). When I catch
the wrigglers I scoop them up in a cup, into a bowl and decant all the crap
out of the water, so that I end up with some pretty clean water with
wrigglers in it.

Sometimes I get a little paranoid that as well as the mosquito larve there
are other less desirable parasitic things in the water that I scoop that
could cause some parasitic problems. Is this possible or am I being overly
paranoid?

cheers