If a clove went into the water, it wouldn't hurt, but when that's happen to me my guys haven't eaten it. They are culinary snobs and want the mixture of yummy fish-meal pellets and garlic :)
Peas clean out their system, so, yes, they are good for them but in small doses. I take my frozen peas and microwave them for 30 seconds and take the shells off and feed each guy about a half of a squished pea. I do this once a week to clean out their systems, or if I see one of my guys is becoming constipated for some reason.