FinFolk are approximately the same size as humans, though slightly heavier. Males tend to be between 5'8" and 6'3" and weight around 210lbs. Females tend to be just slightly smaller at 5'6" to 6'0" and weight approximately 195lbs. Your size is medium. 

FinFolk put a high emphasis on knowledge and education. Their cities boast large and exquisite libraries and cultural arts centers. Education is very important to them, and all FinFolk receive an education starting at a young age and going through until they enter adulthood. Your Intelligence score increases by 1.

Spending their time alternating between the atmospheric pressures of land and sea, as well as swimming against strong currents has made the FinFolk a hearty and durable race. Your Constitution score increases by 2. 

FinFolk are capable of moving freely and easily on land and in water. However, they are much faster swimmers than they are walkers. Your base walking speed is 25 and your base swimming speed is 35.

You have both gills and lungs. This allows you to breathe underwater and above water. There are two variants of FinFolk, those who come from freshwater and those who come from saltwater. FinFolk are only able to breathe in the type of water that they come from. They are still able to swim in the other type of water, but must hold their breath like any other creature. 

You can read, speak, and write Common, Aquan, and one other language of your choice. 

Spending their lives swimming through rapid waters and avoiding things like enemies, rapid currents, and hostile sea creatures has made the FinFolk great at avoiding danger. You get a +2 bonus on dexterity saving throws.