An Immersive Experience 

Recently I had the opportunity while in Nevada to attend the Shark Reef Aquarium. The aquarium itself had quite a variety of sealife, but also had a 3D immersive underwater experience similar to what one may find at some of the major theme parks. While it would be difficult to try to simulate that experience without quite  bit of fancy equipment, the basic concept can certainly be followed.

It can very tricky at an aquarium to get really interesting images. One often has to work around crowds, tour guides, low light or very strange lighting patterns mixed with daylight, reflections, moving animals and, well you get the idea.

While not everyone has experienced sealife closeup in real life, most of us have watched at least one movie in our lives that features the underwater world. To create a very memorable experience for both yourself as well as others looking at your images, an ideal approach would be to create images more than just as though you are looking through a glass wall.

Lighting:

• Most aquariums will have subdued lighting. For this reason you will want a lens with a fairly large aperture (less than f4). 
• Most aquariums will also have path lights or background lights to keep visitors from falling on their face! This can create a major issue with reflections not only from the light, but images of yourself and visitors. Try to move as close as possible to the glass surface with your lens. 
• Be sure to remove any lens filters, you will not need them here. One might be tempted to use a polarizer, but this will only reduce the light to your lens even more.
• There may be lights or even lights with gels within the tanks themselves. Try to avoid those lights in the frame if at all possible. If not, smaller lights can be removed in your editing program.
• Please do not use a flash!

Realism

If you were actually underwater with this creative, what might it look like? Probably not huddled up against a metal plate. Many aquariums simulate natural environments. Try to capture images as close as possible to rocks, coral, seaweed, or any other natural looking underwater props. Be patient, and try to wait until the animal gets as close to midground or foreground as possible. Avoid images that include the back glass plate of the aquarium. Crop in close with your editing program. 

Movement

Unlike people, the animals is not going to stop and wait for you to snap its picture (ok, some might). Watch your shutter speed and do not be afraid to go HIGH on your ISO (1250 or more). Shooting in manual mode will often get the best images.  The ocean often has particulates floating in it all of the time, so a little extra noise in your images is certainly ok. In most cases you will need a shutter speed of at least 1/125 sec to capture moving animals.

Perspective

If you were actually a diver underwater, some animals may be above you, some may actually be below you. When possible, consider different angles.

 During the final editing process, you may need to use filters such as contrast, black and white points, highlights, as well as other controls to get the look that you want. If you take your time, people might actually wonder if you were actually at a undersea adventure!