Bullfrog in your small pond Will it eat your goldfish who is about 4-5 inches big?

I believe the answer to the question would be a firm "yes". Bullfrogs will eat about anything they can swallow even with difficulty. The rest of the answer rests with another question-"how big is the frog"? One additional note would be to tell you I once had a nice set-up containing a few snakes and a rather large bullfrog in the water below. I put a fullgrown and pregnant mouse into the terarium in order to feed the rat snake hanging in the above branch. Before the snake could respond to the rodents presence the bullfrog grabbed the mouse and forced it down its throat totally cosuming it and then sat as if nothing had happened Needless to say I was amazed!