I am not sure if it has been said or not, if you really serious into seahorses, you should contact Dan/Tikidan and/or Liz in MARS, which I forgot her handle.
They are both have been successful with seahorses. They should be able to give you great advise.
Keeping seahorses is a bit different than reefkeeping. A lot of care is needed, BEYOND reefkeeping. Are you sure you are ready for that? What happen if you are going away for vacation? In reef tank you can be automated in a way, including feeding. I am not sure if you can automated seahorse feeding. It is also a little different in a way that if you are not successful from the beginning, you can just sell everything and start from a scratch. It will be more challenging in getting them a good home. Also once a seahorse is sick or weak due to malnutrition, it will be hard to get them back. It will go downhill faster than uphill.
My understanding is that wild caught will be difficult to keep, so you need to source for a captive raise.
They are cute and adorable, so I can understand you want to do a seahorse tank, but please take your time in learning the husbandry before you get the seahorse. Consult with the people that have a great experience with the seahorse.
We will make mistakes in this hobby and resulted in loosing our animal, but to me, there are mistakes that are beyond our control (as we are trying to do our best to mimic mother nature) and there are mistakes that are purely due to our ignorant.
My plea is please please due a lot of research before getting them and if you are sure enough, then get it. I hate to see a thread that my seahorse dying or blow up and finding out it is preventable and the information is all over the place if we look for it.
I am not saying this only to you, this to include reminding myself.
