[VAN BESIEN Hugues]

“They do not like Daphnia.”
Yes, they can catch only the very little one, or moina daphnias, which are “softer”, without dick crust and spines. Moinas are rare in France and difficult to breed a long time. According the way you are breeding daphnias, can be that other, more interessant food is there, perhaps rotifer, cyclops and so on. P. linkei is a bit taller-mouthed as the other species and not so selective with daphnias, but you can’t rely only on daphnias.