[header] How to make a goldfish more interesting [title] Examine your goldfish's behavior. [step] Examine the simple things that your goldfish does and how they react to different types of stimuli. Take notice if they get excited when you get their food, where they like to swim, and what kind of behavior they naturally exhibit. 
This will not only make your fish more enjoyable, but it will also help you understand it when you start to train it. [substeps] Potential tricks include swimming in a circle, swimming under a rock, or swimming backward.