Bigheaded carps (silver carp, Hypophthalmichthys molitrix and bighead carp, H. nobilis) were used to investigate the physiological basis of filter feeding behavior in fish. I developed a new method for assaying chemically based food preferences by tracking the frequency of buccal-pharyngeal pumping behavior before and after a food and food chemical stimuli were presented. Spirulina algae (Arthrospira spp.), a cyanobacterium, was the most potent food type in releasing BPP behavior. Quality and quantity of chemical cues were important to the BPP response. Moderate responses to a mixture of L-Amino acids (common fish feeding cues) confirm their function in this genus but also suggest that there are other highly potent odorants and/or tastants present in the food mix filtrate. BPP behavior was markedly reduced without a functional olfactory sense. These results cumulatively suggest that chemical senses are integral to filter feeding behavior of Bigheaded carp.