Back around '85 I used to read Archie comics. They use to have a sectiion where you could order different gadgets. They also had where you could order seahorses. I do recall odering them and receiving them. They were small maybe dwarf I don't know.
I remember keeping them in freshwater (ad didn't say saltwater) tank and they lived quite awhile of course they died likely due to poor diet (didn't know better at the time).
The reason I mention this is people inquiring about freshwater seahorses and until about a year ago I didn't know there weren't freshwater seahorses..
Just thought I would throw that in.