Marine Ally Feat 5
Source Pathfinder Lost Omens Ancestry Guide
You've befriended a sea creature, which becomes magically bonded to you. You gain a familiar. The type of creature is up to you, but one of its abilities must always be a swim Speed or the amphibious familiar ability.
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
AzarketiAmphibious humanoids who live among the seas of the Inner Sea region, said to have descended from the people of Azlant. Sometimes known as gillmen or Low Azlanti. Azarketi are an offshoot of humans adapted to live in aquatic communities. They have gills, webbed digits, and small fins, and they can survive in or out of water.