diff --git a/puzzles/day06.py b/puzzles/day06.py
new file mode 100644
index 0000000..383181c
--- /dev/null
+++ b/puzzles/day06.py
@@ -0,0 +1,79 @@
+"""
+Advent of Code 2021 - day 06
+
+Run with:
+    python puzzles/day06.py inputs/day06.txt
+"""
+
+import pathlib
+import sys
+
+from dataclasses import dataclass
+from typing import List, Tuple
+
+
+@dataclass
+class LanternFish:
+    reproduce_timer: int
+    children: int = 0
+
+class FishSchool:
+    fish = None
+
+    def __init__(self, times: List[int]) -> None:
+        self.fish = []
+        for time in times:
+            self.fish.append(LanternFish(reproduce_timer=time))
+
+    def simulate(self, days: int=80) -> None:
+        for day in range(days):
+            self._check_school()
+
+    def _check_school(self) -> None:
+        for index, fish in enumerate(self.fish):
+            if fish.reproduce_timer == 0:
+                self.fish.append(LanternFish(reproduce_timer=9))    # Need to correct (should be 8)
+                self.fish[index].reproduce_timer = 6
+                self.fish[index].children += 1
+            else:
+                self.fish[index].reproduce_timer -= 1
+
+
+def part1(inputs: List[int]) -> int:
+    school = FishSchool(inputs)
+    school.simulate(days=80)
+    return len(school.fish)
+
+
+def part2(inputs: List[int]) -> int:
+    school = FishSchool(inputs)
+    school.simulate(days=256)
+    return len(school.fish)
+
+
+def parse(inputs: str) -> List[int]:
+    """Parse the input string"""
+    return [int(value) for value in inputs.split(",")]
+
+
+def solve(path: str) -> Tuple[int, int]:
+    """Solve the puzzle"""
+    puzzle_input = parse(pathlib.Path(path).read_text().strip())
+    part1_result = part1(puzzle_input)
+    part2_result = part2(puzzle_input)
+
+    return part1_result, part2_result
+
+
+def main() -> None:
+    for path in sys.argv[1:]:
+        print(f"Input File: {path}")
+
+        part1_result, part2_result = solve(path)
+
+        print(f"Part 1 Result: {part1_result}")
+        print(f"Part 2 Result: {part2_result}")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/puzzles/test_day06.py b/puzzles/test_day06.py
new file mode 100644
index 0000000..52ba7ea
--- /dev/null
+++ b/puzzles/test_day06.py
@@ -0,0 +1,34 @@
+import pathlib
+import pytest
+import day06 as aoc
+
+INPUTS_DIR = f"{pathlib.Path(__file__).parent.parent}/inputs"
+
+@pytest.fixture
+def example_data():
+    input_path = f"{INPUTS_DIR}/day06-example.txt"
+    return aoc.parse(pathlib.Path(input_path).read_text().strip())
+
+
+@pytest.fixture
+def day06_data():
+    input_path = f"{INPUTS_DIR}/day06.txt"
+    return aoc.parse(pathlib.Path(input_path).read_text().strip())
+
+
+def test_example1(example_data):
+    assert aoc.part1(example_data) == 5934
+
+
+def test_example2(example_data):
+    assert aoc.part2(example_data) == 26984457539
+
+
+@pytest.mark.skip(reason="Not implemented")
+def test_part1(day06_data):
+    assert aoc.part1(day06_data) == ...
+
+
+@pytest.mark.skip(reason="Not implemented")
+def test_part2(day06_data):
+    assert aoc.part2(day06_data) == ...