Copepods come in a wide range of sizes. Many are smaller than rotifers even.
Also, one can selectively sieve out the adults of copepods that are too large, leaving the smaller nauplii to use for food.
Best though to start with small species as that will be easier.
Parvocalanus I think are the smallest that Dan sells, but they are not available to me here in Canada so I use Nitokra Lacustris instead.
I think it works better because of the nutrient profile of the pods, and, as Dan mentioned, the copepods create a better feeding response.
With some copepods I've had good luck, some others the opposite.
Problem is that they don't culture fast enough to give any meaningful numbers for long, so you need a very large culture going long before the fry show up.
I don't get enough to handle repetitive birthings of pelagic fry, so I mix copepods and rotifers for the first feed.
As the fry grow, I add enriched bbs from San Francisco cysts, followed by the larger enriched bbs from Great Salt Lake cysts.
