I believe anchovy syrup is also called "colatura," and can be found in small bottles (usually 200mL or so) in stores that carry a lot of specialty food ingredients. I know one can find it online at zingermans.com, which has been featured in Food52 in their "The Shop" section several times. I have been extremely satisfied with products ordered from Zingerman's.

Its also called 'garum' - it's the same idea as nam pla but more intense. Zingerman's in Ann Arbor also carries it. It's interesting stuff with a very long history; fermenting little fish has been going on a long time. Use a light hand - you can always add a bit more.

( it is traditionally used in Italian cuisine, e.g. tossed with pasta or as a substitute for anchovies, though I haven't a clue as to how much to use)

I bought some and now am trying to find ways to use it.

Chefshop.com

Where do you get anchovy syrup? I've never heard of it.