It wouldn't be strange if you did have a male amongst them. Keep an eye on them as Diesel in Bronzecat's avatar was bought as a female See if you can get some good side shots of them all for us
Those are better They look female at the moment but I would keep my eye on the blue one in your first lot of pics. The little red girl looks to be combtail or carries the CT gene as she has slight double ray extensions on her caudal fin.