What is the ruling on trading in laboratory mice for experimental purposes or merely for children to own as pets?

It is permissible to sell a pure animal if it has a permissible benefit. Those who prohibited the sale of mice justified it by the absence of any benefit in them. However, if there is a recognized benefit in them, then selling them is permissible, such as for medical benefits or scientific experiments. As for selling them as children's toys, it is not permissible, because they are among the fawasiq (vermin) that are recommended to be killed, and playing with them is not a religiously recognized benefit.