Merfolk, like most races/species of beings have their own Religious Deities and Practices. In Greek Mythology their Deity and creator was Poseidon, Roman Mythology it was Neptune. While many mer communities follow the basic guidelines of having one or multiple deities they worship, commonly the practice of Merfolk Roleplayers is to follow the guidelines for using the Deity/Deities are used in the place of actual Mythological Titans/Gods names.  Worship is usually done by a shoal as a whole, recognizing certain times as religious holidays of prayer and sacrifice or making offerings to the Deity/Deities for events such as bountiful harvest, marriage/mating or fertility. Temples have also been constructed in Merfolk societies to honor their Gods/Goddesses/Deity/Deities but due to tidal erosion they often resemble ruins seen on the land. While the building may not look like it once did when constructed, they are still used by Merfolk as sacred places and they are often still used for events such as marriage ceremonies, turning ceremonies, or sacrifice altars.