Kids are fascinated to small colorful moving objects. This is the reason perhaps why some pediatric doctors prefer to have aquariums in their pediatric clinics.
Aquarium in the Pediatric Clinic (image from bronx-leb.org)
However, since most of the kids have the tendency to touch or hold things which are new and amazing to them, it is best if aquariums are situated somehow far from the pediatric exam table. Or might else have it properly attached to the wall so even kids hang on or play with it, it won’t cause any accident then.