Sirena/Siyokoy

Sirena is a mermaid, a sea creature with a human upper body and a fish tail instead of lower extremities. beautiful but vicious they were called Magindara and were guardians of the waters of "asin-palan (Pangasinan)", guarding it from the tattooed raiders from the Visayas. In Pre-colonial Philippines, it is believed that in the full moon or in the Dayaw or Kadayawan, one of the embodiments of the moon who is Bulan descended from the heavens to swim with the mermaids and that the mermaids protected the boy moon from sea monsters. They attract fishermen and lure them to their deaths but sometimes they fall in love.[4] Sirena are reportedly often seen ashore by fishermen, especially in the towns bordering the Pacific Ocean.

Siyokoy are mermen, sea creatures that have a human form and scaled bodies. The Siyokoy is the male counterpart of the Sirena. The lower extremities of a Philippine merman can either be a fish tail or scaled legs and webbed feet. They could also have long, green tentacles. They drown mortals who trespass into their territory. Siyokoy have gill slits, are colored brown or green, and have scaly skin, comparable to that of a fish.