Cadan was a lesser Zoanoid that is a heavy fish shark hybrid. they have suckers on their hands and feet to climb and can shoot jets of water strong enough to tear through a human. They are often produced in large numbers.
In the anime a Cadan appears alongside a large group of Zoanoids alongside Synevite and Lister in an attempt to either kill or capture the Guyver, the lesser Zoanoids attack first all at once but are all destroyed by his Mega-Smasher.