Everything dreeves said completely true. However, you should not feed them within the first twelve hours. In fact you should leave the lights out for the first day itself.
You should try feeding them the night after they arrive but make sure you just drop feed it in there, don't try to aim it to them or anything. You don't want to stress them out.
As you surely know, seahorses stress out alot easier than fish. And the trip there will be drastic for them. So you want to be as careful as possible to keep out of there way and to adjust.
With your new seahorses, please feel free to ask any questions what so ever and please post pictures and progress. I hope you the best of luck.