Do fish have taste buds?
All mammals have them. Lizards have them. Fish have them. Bugs
The "chemical senses" (smell and taste) are the oldest senses,
in evolutionary terms. In some sense amoebas ARE taste buds: they
sense particular chemicals and go towards them. In invertebrate
animals (like insects), some cells are devoted to chemical senses,
and those are the direct evolutionary equivalents of our taste
Tongues are a feature of vertebrates. Every vertebrate has a
tongue, and every tongue has taste buds. They evolved from the
chemical sensing cells in other animals.
(If you don't like the evolutionary version of the story, let's
just say that God decided that everybody needed chemical senses and
stuck taste buds on the vertebrates and in fit of lack of
imagination used the same structures as the chemical sensing cells
on the invertebrates.)
Different species have different taste buds specialized to the
things they're most interested in. Cats don't taste sweetness and
don't particularly require sweetness in their diet. Lots of species
taste bitterness (some humans more strongly than others) both to
avoid poisons and to detect medicines. But everybody's got
Everybody has a sense of smell, too. Smell allows you to detect
chemicals at a distance; taste is what's used right up close. The
sense of smell draws finer distinctions, but isn't very good at
detecting ions that have to be dissolved in water to detect, like
saltiness, sweetness, or sourness.
Not really my answer... I just needed to update the previous
answer for you.