Photos from my first trip to the Vancouver Aquarium after having lived in the city for the better part of five years.
Photos like these, though innocuous-looking, are very difficult to capture. The aquariums themselves are very well-lit but the surroundings are dim at best. Consequently, your camera when on fully automatic mode is almost certainly guaranteed to overexpose the photo resulting in an ugly-looking whitewashed look.
Overexposure can be controlled either by choosing the shutter speed manually, or by selecting a negative exposure compensation. The latter is the recommended technique and will cause the camera to make a more conservative guess on its surrounding light. The above two controls, shutter speed selection and exposure compensation, should be available on almost all standard digital cameras, SLR or not.