I just price them for the levels of what they have such as personalities, colors, kok, body, fins, pearls, rarity, and how well put together they are.
I guess you just gotta do a lot of FH searching or shopping to see what fish is at what value compared to each other.. Also depends who buys and who sells. One can put a higher or lower price for this fish, but that is my price..
A top competition fish can cost as much as a brand new motorcycle or car in hardcore countries like indo and malay... A little bit better can mean a lot over there because when it's competition, a little bit better is better and can bring home the trophy. The FH hobby is a trip.
So basically, the seller just prices his fish for what he feels it's reasonably worth. It also depends on the buyers to make their own judgements. A fish is worth it if it fits the taste, and not worth it if it's not the one the buyer is looking for.