Mostly you have to go into the Everglades, or close to, to see and catch them. Not sure about the East coast, Miami how prevalent they are there.
Albino and piebald are a product of aquaculture - in fact most produced in captivity/aquaculture apprear not to have normal coloration (some one, please, correct me if I am wrong). It's been speculated that the cause of it is line-breeding and inbreeding. Another piece of support for that is that among them there are way too many disfigured ones, missing fins, etc. I own a piebald one I bought in Toronto, Canada that's missing a caudal and one pec fin completely.
By comparison, albinism and amelanism rarely happens in nature (it is a genetic hiccup/mutation) and when it does, the wrongly colored fish stands a 1,000,000 smaller chance of survival - they stand out to sight-oriented predators like a bullseye target.