In vivo, low levels of the peptide injected into male specimens of the Siamese fighting fish causes an immediate aggressive display in this fish in response to their reflection when placed in a mirrored aquarium; High levels of the peptide suppressed this behavior. No effect is observed when injected into mice. Expressed by the venom duct. The cysteine framework is V (CC-CC). Belongs to the conotoxin T superfamily.