How do I find out what type of fish I have?

Ichiro's like 1 & 1/2 inches with a large tail and very fiesty.Hes got like a transparent sorta fin-thing near his gills..like Nemo`s.His eyes are amber goldish,like most fishes.Ichiro's a nice cool aquamarine-cobalt-sapphire-indigo color..very attractive on my boy,too if i say so myself..anyway I cant tell what kind of fish is he..yes I`m sure hes a boy. Hes fiesty and hes in love with my sisters fish Natasha lol ^^