What is a fish teat?
Fish are piscine animals- Pisces- Fish. They do not have teats or breasts as they are not Mammals. Some fish are live-bearers,but they do no nourish their young, the small fry are dropped off like, well, a depth charge bay! Fish do not have breast nipples. Mermaids, if they did exist, would be Mammals, as they would have mammaries and also- mythologists miss the boat here, a mammalian tail like a Seal rather than a fish! this would probably be dappled like some types of Horse.