Hi again,
Oh no, there's no real need to sell the blue daughters. Like I've already mentioned it's a part of the offspring that will turn out blue but also a big part will turn red. But most of the time if you'll cross a blue grass male to a red grass female, more blue ones will develop. Like I've mentioned before, it's not a 100% guarantee but it's a good reference.
You can also use Asian blau (blue) guppies to mix with them (while blue grass already has got an Asian Blau gene in them) to ensure more blue offsspring. But if you'll use an Asian Blau male to cross with red or blue grass females, the Asian Blau gene generates a shorter dorsal of the male offspring.
And you shouldn't be surprised if also one or more (if it happens it's mostly a very low percentage of the male offspring that will turn out being Asian blue phenotypically) males will show up in the offspring. If they occur, they won't show the grass pattern in their fins. Most grass guppy breeders will remove these Asian Blau males for they like to keep the larger dorsal intact.
