I like vinegar eels (actually a nematode) as an easy live food for really tiny fry.
While they are not as easy as microworms to harvest, they are super low maintenance.
Lots of good info on the web, but the short version - keep them in a mix of cider vinegar and water (or vinegar and apple juice) with a small piece of apple in there to feed the bacteria that the "eels" eat.
To harvest - I put some of the vinegar solution in a glass test tube (actually, the one I use is a mouse water tube - http://www.centralpet.com/small-animal/ ... 2-4oz.html ) or arizona ice tea bottle. I put a small wad of filter floss on top of the vinegar, and then put clean freshwater above the floss.
In a few hours the eels will swim thru the floss into the water - you can easily pour them out or use a pipette to extract them and feed them to the fry.
I then remove the floss with tongs and put the vinegar back in the culture.
Long term, eels are no replacement for baby artemia -- but they are a great bridge food for surprise batches of fry (they get me thru the day or two until I have baby brine shrimp ready) or fry that are too small for BBS.