I found this thread interesting........re krill and the scent they give off....I have a 6000 gallon pond with several large Japanese koi in it, they will always rise and come begging for their pellets as soon as they see me, its a conditioned response....
One day I found some dried krill at a pet store so bought some, firstly i noticed they have a strong odour so I bit into one, the taste is very concentrated but did not taste bad at all.,,,To eliminate the conditioned feeding response I quietly entered the pond filter area from the back door, bypassing the feeding area.....I then hid where I could watch the fish and dangled two small dried krill inside the 150 gallon biological open filter located 5 ft before the waterfall,
Within 60 seconds of placing the krill in the filter these freshwater fish which had never eaten krill before were actively circling/searching around the base of the waterfall...it would appear fish indeed have a very keen sense of smell and are especially responsive when the powerful smell of krill permeates their environment.
My fish have since come to love saltwater shrimp as well....will freshwater fish species take saltwater shrimp or krill.....you bet they will, and in a heartbeat.