Thinking along these lines isn't it difficult to call any non-tatagoi as being from a specific breeder?
In general
anything not classified as tatagoi by the breeder is a culled fish. Tosai are killed in the initial culls simply because these have no prospect of ever having any monatary value except as rose food. The investment at this point is marginal but increases as point at which the fish were spawned recedes. At some point the fish will offer the prospect of a return of some sort and can be sold, but call it what you will, this fish hasn't made the grade to some degree and must be gotten rid of.
So where do we draw the line? At what point is a fish worthy or not? Anything a breeder sells much surely represent the genetic traits of its breeder to a greater or lesser degree?
B.Scott