I think seahorses are absolutely cool and apparently they are very sociable. I found a place online that will set you up with all you need to get started at a (I think) reasonable price.
I’ve never had a salt-water aquarium before. How much work is it? Is it expensive to keep up?
My understanding is that they are very difficult to keep, even for someone experienced with salt water aquariums. I asked the same question of a couple of friends a few years back, and they kindly took me to an aquariums specialising in sea horses. I was told sea horses almost all die very soon in captivity because it is -
a) very difficult to get the environment right
b) feeding is is tricky (live food only)
c) they are vulnerable to disease
Obviously you would learn by experience, but many species are at risk.
I was at a seahorse exhibit with Kyla and Dynosaur recently, at the Shedd aquarium. They had a pretty big display on how endangered some of them are. I’d want to be absolutely sure that any seahorses I got weren’t endangered and harvested from the wild.
I don’t think that you need live food for seahorses, it might be perfered but I don’t think they will not eat other foods. The best thing to do is to keep some live rock in the tank. However, I understand that they are very slow eaters and do well only when they are by themselves because they may not eat otherwise. That’s all I really remember about keeping them though sorry.
But just think! If you can pull this off, and then tame them, you’ll kick ass at water polo!
Um.
Never mind.
I had seahorses for quite some time, along with a few other saltwater aquariums. They are a gigantic pain in the rear, but beautiful and very cool to have. The downside is they’re very expensive, and despite the fact I’d had saltwater aquariums for a long time and exceptionally careful with them, they still had a poor survival rate. I had one of them survive for just over a year, that was the record by a longshot.
I kept them in a nice, big, seperate tank from anything else, kept no more than 6 but no less than 3 together at once. I fed them live food, they didn’t eat anything else (but some will). I also kept a good bit of live plant material in the tanks, they did much better with than without. Keep the tanks absolutely away from direct sun; e.g. keep them on the same wall as the sole window in a room.
That’s all I can think of off the top of my head - I’ll check back in if I think of anything else.
I know nothing about keeping salt water aquariums, but I do know that last time I was at an aquarium (either the Shedd in Chicago, or the nice one in New Orelans, whatever it’s called), I was talking to one of the people who works there about the sea horses they had on display, and why I never saw anyone who had them in a home aquarium. They said they are incredibly difficult to keep - very delicate. I’d take the word of a professional, along with the folks in this thread.
I kept seahorse for a number of years. I had a variety of species from dwarf seahorses (Hippocampus zosterae) (about 1.5 inches full grown) to the king of the sea the H. Erectus seahorse. Reason for dropping them - not enough time anymore. Maybe one day again.
Any good saltwater aquarium keeper could keep the water conditions quality pretty stable, so that is not an issue. However the biggest issues seem to be stress and parasites and as Smashed Ice Cream stated food. A normal well established fish tank can get by with feeding 2 - 3 times a week. A seahorse tank will need to be fed twice a day every day. The reason, Seahores do not have stomaches.
There is a lot of work involved in keeping seahorses. For Dwarf horses they only eat live brine shrimp. So you have to hatch brine shrimp every day and sometimes twice a day depending how many dwarves you have. The problem here is that a lot of time the brine eggs will have hydroids (like very small jelly fish. They feed on plankton but in a closed environment artemia or brine is more then sufficient) attached to them or they are introduced via plants or other items in the tanks. These little critters will kill a seahorse or even a whole take very quickly. They will get into the gills and basically suffacate the horse. Not a pretty sight.
So you move on to the larger species. While they tend to be more resilient, there are issues with them as well. Again the situation in either case here is food. Wild caugfht seahorses (a problem in itself, sometime they use cyanide to make their catches … 
) will only eat live food. This will mean a separate tank just to keep you live shrimp in (Ghost shrimp work well but need to be gut loaded).
(At one point I had 5 differnt tanks just for feeding my 2 tanks of seahorses. Different stages of brine growth and a couple types of shrimp.)
Advances in breeding techniques have led us to captive bred and raised horse that will accept frozen food. This is the only way to go if you ask me. Less room for parasites, less room for bad capture practices and the most important is we are not dwindling our ocean resourses down. 
(Did you know some seahorses are now on the endangered list due to over farming. Not only do we have these beautiful creaters in our aquariums but in the east they are considered a delicacy.)
I could go on and on, but I will conclude with saying that if you have the dedication, the determination, and lots of time it is truely a wonderful experience and it is nothing like any other animal I have kept. Especially when they are courting. They will swim every where together tails linked. And when a birth occurs look out. For my largers horses I had as many as 250 babies in one birth. What is so cool about that is the babies look JUST like the adults only about a 1/4 inch in size.
Thought you might want to check out this site. In my experience this probably will be able to give you the most information. Don’t be afraid to ask questions.
Thanks everyone for your input. Yes, the seahorses I had in mind are bred and raised on a “ranch” (that’s funny) so I wouldn’t be kidnapping them from the wild.
slallen, thanks for the detailed post. It looks like I would neither have the room nor time for seahorses at present. But they’re so damned cute! I think I’ll stick to a freshwater tank for the time being.
That said, what do you do with 250 babies?! (I know, I know, get a bigger tank!).
Yes another tank is correct. However success rate (unless you have a huge amount of time is very low. ‘Ranchers’ have specialized equipment and lots of resources.
Babies are extremely difficult. I mean you think adults are bad … OMG.
Anyway glad I could help and best of luck!
aren’t there a fresh water type? i vaguely remember having sea horses as a kid and we did not have an elaborate set up. there was bowl, water, food, and horses.
Are you sure they were not sea monkeys. The packaging shows what appear to be sea horses and in fact they are brine shrimp.
To my knowledge there are no fresh water seahorses.