I may be wrong, but I don't believe those pics are of the Miami Serpentarium. That facility was located right on route US1 and wasn't near a large body of water as shown in those pics. I was there as a young child myself, probably in the late 50s, and the facility had a large stone fence around it as well as an impressively large sculpture of a cobra. The enclosures inside did not have any sealife, only reptiles.
My guess is that perhaps these are early images of the Miami Seaquarium, instead...