About 50ml starter culture of Paramecium caudatum from my own culture that I started from a local biological supply house culture.  When I picked it up a few months back I was told that it isn't a pure culture and that other protozoans were included.  While I've found that to be true, the vast majority of the culture is Paramecium.  I used this culture to raise my dwarf emerald rasbora and rainbowfish fry.  If you're going to raise scarlet badis, betta, or CPD fry, this is the culture you should start now.