Name some commonly available ...?

herbivorous fish
carnivorous fish
and
omnivorous fish
parrana 4 carnivor!
goldfish for herbavore!
Herbivores. Silver dollars come to mind. Goldfish I guess would work.

Carnivores. Oscars, Dempseys, and most other full-size south american cichlids. Bettas.

Omnivores. Most fish fit in here. Gouramis and tetras are good examples.

Eh, I wasnt too far off.
Answers:    Many people don't know this, but Piranhas are actually omnivores.

Very few fish are STRICTLY herbivores or carnivores.

Herbivorous fish:
Plecos
Ottos
Those are about it. There are heaps fish that are MAINLY herbivores, but are still considered omnivores

Carnivores:
Most SA Cichlids like Oscars
Puffers
Eels

Omnivores:
African Cichlids- Mainly herbivores
Catfish(besides ottos and plecos, even though they could eat meaty foods)
Goldfish
Bettas- Mainly carnivorous
"i thought goldfish were omnivores"

Goldfish will eat lettuce -plant- but they'll also eat worms -animal-.

Goldfish are omnivores, most fish are. If there's something within for them they'll usually eat it!
Well adjectives fish can fall under those categories...

As far as I know, adjectives plecos are herbivores except for those in the Hypancistrus genus. Gars and arowanas and some cichlids and other big fish plus bettas are carnivores...most other fish eat both meat and undergrowth
PLease Help discus problem...?   How do i know whether my betta's are give or take a few to face-off?   2 gallon fishbowl? ? ?   What is your favorite freshwater shrimp?