The active components of the cone snail venom are a group of neurotoxins called conotoxins. These are usually 12 to 30 aminoacid residues long. The peptides are highly constrained due to high density of disulphide bonds.
Although conserved structures are present in these peptides there are also subtle differences. These differences are responsible for the high toxicity and high specificity. These differences also ensure that each species has a unique subset of toxins. It has also been found that sometimes, the toxins differ even among individuals of the same species.
The conotoxins present in the fish eating cone snails are more effective against humans than those present in the mollusk eating snails.
The cone snail venom causes paralysis. The paralytic conotoxins belong to three main classes: alpha, mu and omega conotoxins. There are also others ... delta and kappa conotoxins.
You will find a list of conotoxins here.