Dive tourism, with proper diver training, has been suggested as an environmentally benign and economically viable alternative to commercial fishing on reef fish spawning aggregations (FSAs). Yet, the disturbance effects of divers on the FSAs must be assessed to ensure that the resource is sustained. We examined over 9 hours of video footage (extracted from over 100 hours of underwater video) filmed at FSA sites in Belize. The footage captured divers interacting with schools of snappers and groupers as they aggregated to spawn. Video also captured diver interactions with whale sharks. Diver behaviors included observations, video recording, flash photography, and tagging of whale sharks. We filmed 746 unique diverschool interactions that included total observations of approximately 200,000 snappers, 4,700 Nassau groupers Epinephelus striatus and 200 whale sharks. We recorded 180 spawning events, only 105 of which showed divers disturbing aggregating schools, which affected an estimated 2,100 snappers and 90 groupers. We conclude that small groups of experienced divers, following a code of responsible diving centered upon the precautionary principle and sensitivity to fish breeding behaviors, do not negatively affect schooling or spawning behaviors. Though further research is needed to assess the effects of boat traffic, underwater sound, and larger groups of less experienced divers, dive ecotourism at FSAs represents an economically attractive and less exploitative alternative to commercial fishing.