In fishes, upregulation of hsp40 has mainly been documented in response to exposure to infection agents, including in Paralichthys olivaceus (olive flounder), Epinephelus coioides (orange-spotted grouper), Ictalurus punctatus (channel catfish), and Carassius auratus (Crucian carp) [40–43]. This evidence concerns the gene DNAJB1 and infection.