Itay,
There is a species of seahorse called H. kuda, so that is probably what they are. From how you describe feeding them, I suspect they are wild caught (WC).
Brine shrimp are a poor source of nutrition and should not be considered a long term food source for your new kudas. Rotifers are very, very small and may be overlooked by your kudas. Even though there may be lots of pods in the tank, your SHs will soon eat them, especially kudas which grow pretty large, maybe 8" or longer at full adult size.
Rotifers are perfect food for kuda fry, though, which need to be raised separately from the adults in nursery tanks. Interestingly, kudas which are large, produce hundreds of very tiny fry. The H. whitei that I keep are small (4" adult length) and produce smaller broods of quite large fry.
The sooner you get your SHs eating frozen the better. PE mysis, available from J&L and a few select lfs, are the best nutritionally for SHs of all species except for dwarves with an adult length of only about an inch, which eat only newly hatched brine.
Training your kuda to eat from a feeding station will cut down on overfeeding. Here is a site I put together on various feeding stations and training methods:
http://www.lostmymarblz.com/hh-feeding-stations.htm
HTH.