Agree with above,when I research fish I am more interested in what water parameter's the fish need in order to thrive with respect to Temp,pH,GH,KH. Usually these fall pretty closely in line with other sites,or books.Water parameter's hold more value to me than opinions on compatibility with other fishes ,for if the water isn't suitable for the fish,, then it's not gonna much matter whether the fish gets along with other fishes.I try to keep fishes somewhere in the middle of their recommended range for the afore mmentioned water parameter's rather than attempting to keep them at upper or lower extreme.
Compatibility takes in a lot of factors,Tank size,types of fish,adult size of fish, temperment with like species as well as other species,areas that fish frequent in the aquarium, Diet, planted or un-planted tank,substrate material, etc.
Some fish get along with fishes they aren't supposed to(or maybe not) when small ,but as the fishes mature,things can turn.
Seem's no matter what those with expierience suggest ,there is always the odd duck that declares..(Well, I know a guy...) or,,,( My fish does just fine, Blah,blah,blah.)
This is where many become confused.
Research the fish not opinion's,,and things are a bit easier in my expierience.