I remember ads for sea horses in many comics and magazines. Right next to the X-ray glasses and fake dog poop. 
I never ordered them. I’m curious if sea horses arrived alive? Back then it took a couple weeks to get orders by mail. Unless they shipped by air mail.
I’ve heard sea horses are actually tiny. Did they make interesting pets? Did they live long?
Sea Horses range up to a little over a foot long.
Though the pygmy is only about an inch.
I don’t remember those ads, but I do remember Sea Monkeys which were brine shrimp and tiny. Those did arrive and some lived.
I remember the sea monkey ads.
I understood even at 11 that most of these products were questionable.
I did buy a goldfish and bowl. The stink was terrible. I changed the water too often and it killed the little guy after a couple weeks.
I had better success with Betta fish. Didn’t stink and it lived over a year.
Sea monkey? How about a real monkey?..
$19 was 5 weeks allowance. I couldn’t afford it.
I can imagine my mom’s reaction if a monkey in a box arrived in the mail. 
What year were they still offering monkeys? That seems crazy even for the 60s.
Monkeys were all the rage in the early 60’s after they launched them into space. I recall watching Lancelot Link, Secret Chimp on Saturday mornings in 1970.
Apparently between 1968 to 1972. Mail Order Monkeys - Desperate Living
Monkey Madness : NPR
And as an added bonus: When you could buy a monkey from the Sears mail-order catalog - Boing Boing
My grandfather got a monkey in the late ‘Fifties or early ‘Sixties. It was, as you might imagine, a real menace in the household and was sent upstate to a nice farm (or whatever you do with primates) after smashing a bunch of my grandmother’s prized fine service.
It wasn’t until the ‘Seventies that the US federal government started cracking down on the importation of exotic ‘pets’, and most states didn’t really regulate the keeping of exotic and wild animals until the ‘Eighties. Even today, you get a lot of people trying to raise bobcats, foxes, raccoons, and bears without any clue as to the difficulty and danger (for both the owner and animal) for someone who is not an experienced rehabber.
Stranger
I saw some seahorses (one word?) with young at an aquarium, New Orleans, I think? They’re incredibly delicate and tiny versions of the adults which are themselves tiny and delicate. But, the little ones seemed to get around ok on their own and like they might survive a few days of travel if it doesn’t get too cold.
Sea Monkeys were real. You got a dried little packet of eggs that could survive and then come to life after being added to water. Could it be that you got dried sea horse eggs?
Dang, people ordered these and they survived? Sea horses are considered fairly advanced saltwater fish to keep.
The Sea Monkey(fairy shrimp) ads weren’t of any interest when I was growing up in San Diego. There were vernal pools full of them in the undeveloped areas a couple of blocks away. Of course now vernal pools and the shrimp are are a rarity in the county. In places like the Santa Rosa Plateau they’re sort of a major attraction after a wet winter/spring.
The item that I wanted from those comic book ads was the x-ray glasses.
There’s a family tale(can’t verify its truthfulness)
My Mother wanted to order the Grand Canyon donkey off the back of a Sears catalog. Her Daddy wouldn’t for various reasons.
So she worked at the store, saved all her money gifts. Got the $59.99. Then found out shipping was $40 more. Somehow she convinced her great Aunt into paying that. She ordered it.
What she got was a decrepit, sick old Donkey of unknown heritage.
After a pretty big vet bill for its feet, it was determined it had to be euthanized.
Moral: never buy sight unseen.
No. Sea horses (famously the fathers) give birth to live young.
You could get sea monkeys at the drugstore. It wasn’t just a mail order thing.
Well, they carry the fertilized eggs in a pouch that they then come out of, so it’s not quite a placental pregnancy.
Sea horse eggs can hatch outside the male, too, although there’s a lower rate of viability. But I’m not sure if sea horse eggs can be shipped. The only fish whose eggs are shipped dry to my knowledge is the Killifish.
I never bought any sea monkeys, at least not from magazines back when those ads where all over the place. But I do hatch and feed live brine shrimp to my fish.
One of my college housemates loved kitch and definitely “raised” sea monkeys in the 80s that he bought locally.
By the way, Killifish breeding is quite the rabbit hole.
There are endless varieties of Killifish, some of them are quite stunning.
In the wild, they live in pools of water that fully dry up in the dry season, at which point they all die. But before they all die, they dig in the mud and lay eggs. The sun bakes the mud and the eggs stay safe deep inside. Then the next year the rains return, and the fry hatch.
In the aquarium, they can actually live longer than a year, although not very well - by year 3 or 4 they’re clearly past their “expiration date”. But they can be bred for multiple years if desired.
I forget the details, but I listened to some podcasts on the process. You get them to lay their eggs in a tray full of mud which you then dry out (it has to get dry enough before being rehydrated or the eggs won’t hatch, which is an evolutionary advantage to ensure that the eggs don’t hatch early, before the rains return).
So it’s not exactly easy to breed them, but it can be very profitable. The eggs, once dried out, can be shipped in the mail, just like brine shrimp eggs. So you can sell them to a wide geographic area pretty easily, and they’re not too common and very pretty, so there’s always demand.
Fish breeding sounds like a really fun hobby for when the kids are older and I have more time.