The Trix Dark Sirenix

The outfits consists of a body suits that is less revealing and darker than Sirenix, a pairs of stiletto, a glove made of the same material with the outfit cover a hand and even the socks covering the girls' legs. They wear smeared makeup on there eyes and lips. The hair mostly stays in ponytail or pigtails. Instead of seashell-shaped wings, they gain tentacles.

After Tritannus forced Daphne to tell him where the source of Sirenix power was, Tritannus headed to Lake Roccaluce to destroy the Source of Sirenix permanently, so Daphne cannot protect her Sirenix from being stolen by him. After he destroyed the source (which was later restored by the Winx using their Harmonix powers and the powers of the Selkies), Tritannus absorbed Daphne's Sirenix powers and used his trident to give a dark version of Sirenix to the Trix. It is unknown how the Trix still keep their Dark Sirenix even Tritannus loses his power and trident