I went to a lovely lecture last night at Lewis & Clark on cone snails and I must share some awesome videos of cone snails attacking fish. The lecturer was Dr. Toto Olivera of the University of Utah. If you missed the lecture, luckily he has a very similar lecture uploaded online here if you have some free time and want to learn more. You could also explore his website, http://www.theconesnail.com/, which is highly informative and easy to understand.
Cone snails are venomous, predatory mollusks. Depending on the species, they will hunt either fish, worms, or other mollusks. The fish-hunting cone snails have evolved two different fish hunting techniques: hook-and-line fishing and net-fishing, as seen in these videos:
In addition to using different techniques, these two different hunters also use different types of toxins on their prey. The hook-and-line fishers use strong excitotoxins which cause stiff paralysis (its like the fish version of a taser). The net-fishers use sedative toxins, effectively drugging the fish with opiates as they are being engulfed by the snail.
More on cone-snail predation: http://www.theconesnail.com/explore-cone-snails/prey/piscivores