I thought they were called Dancing Shrimps.
I had Sea Horses at one time, many years ago.
Marine fish are so expensive now, so we stick to the tropical.
Fish tanks are great for minding babies too as I discovered with my first kids in the UK. I bought an aquarium fish DVD for my grandkids when I looked after them and they were strapped onto a bean bag.
Still got it somewhere, it is very relaxing.
I used to have gropers to clean my tank all those years ago, I liked them but my wife only like tetras and pretty fish. I think the gropers only came out at night (that might not be the right name - they looked like a grey green cat fish with the mouth at the very bottom of the head)