As an underwater photographer, Cai is very keen in blackwater diving where he is able to explore different kinds of marine life. He is also fond of blackwater photography because for him, it is one of the mediums where in the wonder of these sea creatures are emphasized, as the stars shine brighter in the pitch black skies, the dark seas also give his photo subjects this unique glow that can only be attained in black waters. In the recent years, Cai’s work have been featured in various magazines and marine research books with some even winning awards in various international competitions.