He tenido la oportunidad de bucear junto a tiburones nodriza en varias ocasiones y, en efecto, nunca se han mostrado agresivos, todo lo contrario. Pero se ve que en tu caso, la posibilidad de cazar y alimentarse con el mínimo esfuerzo les ha puesto un poco nerviosos. Bonita experiencia.
I have had the opportunity to dive with nurse sharks several times and, in fact, they have never been aggressive, just the opposite. But, in your case, maybe the possibility of hunting and feeding with the least effort has made them a little nervous. Nice experience. 