Tilapia piscidin 3 is an antimicrobial peptide with antibacterial activity against gram-positive and -negative bacteria (MIC: 2.44, 2.44, 9.78, 19.55, 0.61 μg/mL for V. vulnificus 204, V. alginolyticus , S. agalactiae 819, E. faecalis BCRC 10066, S. agalactiae BCRC 10787). Tilapia piscidin 3 has hemolytic activity in fish red blood cells.