Not everyone is a fan of snails, but there’s no denying the benefits they bring to a freshwater aquarium. Aquatic snails are ...

Leeches might seem like relics of a bygone age of medicine, but they haven’t outlived their usefulness to people yet. The freshwater leech Helobdella austinensis can eat its weight in snails every day ...

Neritina canalis with its eggs. Each egg contains a few hundred larvae that will be washed down into the ocean. Photo from Eric Krandall Many animals do not spend their lives entirely in saltwater or ...