I think I may finally have the basis for a breeding group of yellow ramshorn snails. Which is to say i have at least two of them, possibly three. I think I can safely assume that the lack of red body pigment is a recessive gene. But on the up side ramshorns are hermaphrodites so any two can start the true-breeding line, although I am leaving a brown ramshorn in with them so I can select out the yellow ones and avoid massive inbreeding.