well first off what size is the tank/ is it decorated/planted? Are you sure that the male cory wasn't latching on to the betta in any way (unlikely but still possible) and the betta was fighting it/ "guarding his territory"? And are you sure the betta was actually displaying mating poses or really just defending himself/territory? Also if food distracts him then that means 1. you scared/ snapped him out of it or 2. he's bored. Lol i love how everyone else is so playful then there's me