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I've had to do it for seemingly healthy, but obviously physically defective fish. I've been selling fry, and in no way, shape, or form, should runts or deformities be distributed. Not out of cruelty, but to maintain the integrity of the species. Ad Konings even states this in several of his cichlid books. IMO there's a good chance that most of them would not survive in their natural habitat also, either rejected/chased or eaten by others.
11 tanks, 5.5g up to 125g(2). Mbuna, Haps, Peacocks, Tangs, wild caught to tank raised!