Guppies are fine if you know the source is clean, or do like I do and breed them yourself. Goldfish are not recommended as they tend to have parasites more often than other fish. I can't do nice either...just can't bring myself to do it, even frozen. I do, however, feed mine freshly molted dubia roaches and he loves them. I'm not sure if breeding and housing roaches is legal in Canada though. You'd have to check that out first.