|Coral Display at the Steinhart Aquarium (author's photo)|
It's sometimes easy to become overly focused on looking for the "exciting" animals (aka. things that move) in large public aquarium displays, but it turns out that one of the most amazing feats of aquariology are those that you might overlook- coral. Shepard told me that keeping coral in aquariums was something thought impossible until the 1970s- and not widely performed in personal and public aquariums until the 80s.
There are two important components to keeping corals alive in captivity: an abundance of plankton and intense sunlight (or UV light). In the 1970s, several German public aquariums, and a few curios hobbyists throughout the world, started experimenting with aquarium systems that utilized unfiltered saltwater. Unfiltered water helped provide the coral with enough plankton for food. In addition, the aquarium was exposed to direct sunlight. These two components components kept coral alive in captivity, and keeping coral started to catch on. Other institutions, including the Waikiki Aquarium in Hawaii, notched it up a scotch and started maintaining and propagating multiple coral species and providing other public aquariums with new species.
By the 90s, keeping coral was settling into normalcy- hobbyists and aquarists were confidently keeping coral alive for extended periods of time, and also setting up systems to grow and propagate their own coral so that they didn't have to destroy reefs in order to stock their systems. But the system is still problematic- more coral is shipped from tropical regions and sold than is propagated from existing exhibits. This trade hurts marine systems as much as the fish trade. But practitioners are optimistic that coral propagation (by fracturing and sexual reproduction) will eventually slow this trade.
So: When you're looking at a huge aquarium display, look past those little fishes to see something truly amazing and precious- living coral!
For more information on the history of coral displays in aquariums, the craft of keeping corals, and the difficulties with the coral trade see:
J.Charles Delbeek Coral Farming: Past, Present, and Future (2001) and Bruce Carlson Aquarium Systems for Living Coral (1987)