Seahorses are a bit of a challenge they require perfect water conditions. Do not ever purchase one that is wild caught, they are almost impossible to feed.
If you choose to do seahorses ask your LFS to feed them for you. Or purchase from seahorses.com they have several tank raised species and can give you good info on proper tanks for them.
Pipe fish are much easier to keep but need to have copepods in the aquarium for them to munch on all day. Most will take frozen food but that will not sustain them for long periods of time. Let me know if you have any other questions, I can go on and on and on..... :)