Background: Fish skin mucus contains innate immune factors and acts as the first line of physical or chemical defense against pathogens. Objective: The primary aim of this study was to determine the antiviral activity of sea bream (SBr), rainbow trout (RT), and sea bass (SBa) fish skin mucus against herpes simplex virus (HSV)-1. In addition, it was aimed to associate possible antiviral activity with antimicrobial peptides (AMPs) such as cathelicidin, hepcidin, galectin 2, and C10ORF99, whose levels were determined in the mucus. Methods: The antiviral activity and oxidative/antioxidant status of mucus against HSV-1 virus was evaluated. In addition, AMPs, SOD, and CAT activities, and immunoglobulin M levels were also analyzed in mucus of fish. Results: Antiviral activity mucus of SBr, RT, and SBa against HSV-1 were determined as 2−4, 2−5, and 2−2, respectively. The higher antiviral activity of SBr and RT mucus compared to the mucus of SBa can be associated with higher AMP levels in them. Conclusion: The skin mucus of SBr and RT may be nutritional supplement, adjuvant, and a new agent that can potentiate the effects of antimicrobial/antiviral agents.