Perhaps the single event that most shaped Monterey in recent decades was the opening of the Monterey Bay Aquarium in 1986. This aquarium specializes in the unique marine life of the Monterey Bay, and millions come to Monterey each year, largely to visit the aquarium. The aquarium’s founders chose their site well. The location is rich in history, and was previously the site of the famous Hovden Food Products Corp. (1916-1973), where Portola Brand sardines were canned. The aquarium also overlooks one of the calmest and most comfortable dive sites in Monterey —Aquarium Reef.

Aquarium Reef begins near shore and gently drops to a sand bottom at about 60 feet. This is a low-profile reef, with ridges of granite that run approximately parallel to shore, separated by sand channels. The rock rarely rises up more than several feet above the bottom. This reef supports a large bed of giant kelp, which can be very thick in summer months, but is rather thin in winter. While there are many places to drop anchor here, one of the more interesting anchorages is a spot called Aquarium Wall.
Here the wall begins in 40 feet of water and drops in stages to the 55-foot bottom. The higher relief reef allows the local critters to take full advantage of the rich, nutrient-bearing currents, and marine life here is a bit better than the rest of Aquarium Reef. The highest profile wall only runs for about 100 feet, so this spot can easily be explored on a single tank. The rock here is not smooth, but is sculpted with a wide variety of cracks, fissures, bowls and small caves. This is not the type of site to sit back and enjoy the grandeur of the reef; it is the type of site that requires you to get your mask close to the reef and look for the little critters on the rocks and back in cracks.
Aquarium Wall is a great place for fish watching and fish photography. Throughout the year small rockfish hang close to the reef or among the kelp fronds. Countless sand dabs and starry flounders are found in the sand channels. Look for gobies and little sculpins perched on top of sponges or hiding in cracks. 
In winter and early spring this is a particularly good spot to photograph nest-sitting cabezon and lingcod. In both species, it is the males who assume the job of househusbands, and guard the nests, while the females depart for deeper water. Usually divers find males throughout the year, but the larger females are only seen during breading season.
Aquarium Reef has its fair share of nudibranchs and these are generally hard to miss due to their bright colors. Most of the several dozen species found here are dorids, but there are many aeolids and even a few dendronotids. Some nudibranchs can be very small, so you will have to get close to the rock and look carefully. Others, particularly dorids, can be the size of your fist. The outrageously colored horned nudibranchs are common here.
The rocky bottom is home to some large invertebrates: sunflower starfish, large anemones, sea cucumbers and sponges, but the smaller critters steal the show here. Back in the cracks you will find several species of shrimp, crabs and tunicates. Look for abalone back in the deeper cracks. Move slowly and look carefully and you never know what you will find. There are tiny, bright orange amphipods that live among the nudibranchs. Tiny barnacles live on the backs of snails.
Divers often see otters on the surface, but rarely underwater. They are normally seen wrapped up in a bit of kelp, napping; trying to open a clam with a rock; or grooming their rich fur.
The giant tanks of the Monterey Bay Aquarium have become a looking glass for non-divers to at least partially experience what we divers have known all along‚äîthe thrill of being underwater is without equal! Nowhere is this more evident than at Aquarium Wall.
The author would like to thank Captain MaryJo Nelson and the crew of the Beachhopper II for their help in the preparation of this article. 
Location: Offshore of the Monterey Bay Aquarium at: 36°37.178′ N, 121°53.904′ W.
Access and Facilities: Boat dive only. Private boats may be launched from the public ramps Monterey Breakwater or between Fisherman’s Wharf and Wharf #2.
Depth: 40 to 55 feet.
Visibility: 20 to 40 feet 
Skill Level: Beginner or better.
Hunting: This site is right on the boundary between the Lovers Point State Marine Reserve and the Edward F. Ricketts State marine Conservation Area. The Conservation area only allows the taking of finfish by hook and line; the reserve is a no take area. Divers may take nothing.
Photography: Great macro and fish photography even on days when the  visibility is poor. Wide-angle photography can be challenging here.
Hazards:  Watch for surge, and boat traffic.