Cika wannan jumla: Castellanos ya yi gasa ne kawai a cikin
maza 100 m freestyle a gasar Olympics ta 2000 a Sydney. Ya sami wuri na duniya daga FINA, a cikin lokacin shigarwa na 53.43. Ya kalubalanci wasu 'yan wasa bakwai a zagaye na uku, ciki har da George Bovell mai shekaru 16 da haihuwa na Trinidad da Tobago da kuma' yan wasan Olympics na Seychelles sau uku Kenny Roberts. Ya kammala filin zuwa na karshe a 54.06, kawai 0.63 seconds a kasa da tsarin shigarsa. Castellanos ya kasa ci gaba zuwa wasan kusa da na karshe, kamar yadda ya sanya na sittin da hudu a cikin prelims.