The authors report 7 cases of allergic respiratory diseases such as asthma, allergic rhinitis and bronchitis, induced by non-occupational contact with pet-fish food. Food for pet fish contains proteins of a variety of arthropod species (larvae and adult forms) --e.g. Chironomus, Daphnia, brine shrimps and others --as well as fresh-water worms such as Tubifex, Enchytraea etc. Thus far only hemoglobins of Chironomus have been well studied with regard to their antigenic role; sensitization against Chironomus was noticed in most of our patients. Daphnia is also known to be a specific allergen. Atopic patients often become sensitized against further respiratory allergens (5 out of the 7 patients had a previous allergy against pollen). Accordingly, patients with respiratory diseases of already known allergic origin should, in our opinion, give up not only mammals or birds as household pets but also an aquarium.