I'm new in dotNet development and trying to create an API with response  having  decimals. I'm expecting that the API will show 0.000000 but instead only shows 0.
This is the data from my database

public class InvAmt
    {
        public double buyWsAmount { get; set; }
        public double buyRetAmount { get; set; }
        public double sellWsAmount { get; set; }
        public double sellRetAmount { get; set; }
    }
[HttpGet]
public async Task<ActionResult<List<InvAmt>>> GetInvAmt()
 {
   var connString = _config.GetConnectionString("Mysqlconn");
   using (IDbConnection conn = new MySqlConnection(connString))
    {
      string sql = $@"SELECT pa.buy_ws_amount AS buyWsAmount, pa.buy_retail_amount AS buyRetAmount, pa.sell_ws_amount AS sellWsAmount, pa.sell_retail_amount AS sellRetAmount FROM product_amount pa;";
      var res = await conn.QueryAsync<ProductCategory>(sql, null);
      return res.ToList();
     }
  }
API response
[
  {
    "id": 1
    "buyWsAmount": 1300,
    "buyRetAmount": 26,
    "sellWsAmount": 1800,
    "sellRetAmount": 36.000001,
  },
  {
    "id": 52
    "buyWsAmount": 0,
    "buyRetAmount": 0,
    "sellWsAmount": 0,
    "sellRetAmount": 0,
  }
]