diff --git a/6/6.py b/6/6.py
new file mode 100755
index 0000000..bb8f882
--- /dev/null
+++ b/6/6.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+# 2021 - Advent Of Code - 6
+
+def parse_file(file):
+    with open(file) as f:
+        line = f.readline()
+    return [int(x) for x in line.split(',')]
+
+
+def iterate(state):
+    new_fish = 0
+    for i in range(len(state)):
+        if state[i] == 0:
+            new_fish += 1
+            state[i] = 6
+        else:
+            state[i] -= 1
+    state.extend([8]*new_fish)
+
+
+init_state = parse_file('input.txt')
+print(f'Initial state: {init_state}')
+
+DAYS = 80
+
+for d in range(DAYS):
+    iterate(init_state)
+    # print(f'After {d+1:2} days: {init_state}')
+
+print(f'There\'s {len(init_state)} lanterfish after {DAYS} days')
diff --git a/6/input.txt b/6/input.txt
new file mode 100644
index 0000000..6b5d079
--- /dev/null
+++ b/6/input.txt
@@ -0,0 +1 @@
+3,5,3,1,4,4,5,5,2,1,4,3,5,1,3,5,3,2,4,3,5,3,1,1,2,1,4,5,3,1,4,5,4,3,3,4,3,1,1,2,2,4,1,1,4,3,4,4,2,4,3,1,5,1,2,3,2,4,4,1,1,1,3,3,5,1,4,5,5,2,5,3,3,1,1,2,3,3,3,1,4,1,5,1,5,3,3,1,5,3,4,3,1,4,1,1,1,2,1,2,3,2,2,4,3,5,5,4,5,3,1,4,4,2,4,4,5,1,5,3,3,5,5,4,4,1,3,2,3,1,2,4,5,3,3,5,4,1,1,5,2,5,1,5,5,4,1,1,1,1,5,3,3,4,4,2,2,1,5,1,1,1,4,4,2,2,2,2,2,5,5,2,4,4,4,1,2,5,4,5,2,5,4,3,1,1,5,4,5,3,2,3,4,1,4,1,1,3,5,1,2,5,1,1,1,5,1,1,4,2,3,4,1,3,3,2,3,1,1,4,4,3,2,1,2,1,4,2,5,4,2,5,3,2,3,3,4,1,3,5,5,1,3,4,5,1,1,3,1,2,1,1,1,1,5,1,1,2,1,4,5,2,1,5,4,2,2,5,5,1,5,1,2,1,5,2,4,3,2,3,1,1,1,2,3,1,4,3,1,2,3,2,1,3,3,2,1,2,5,2
diff --git a/6/input_example.txt b/6/input_example.txt
new file mode 100644
index 0000000..55129f1
--- /dev/null
+++ b/6/input_example.txt
@@ -0,0 +1 @@
+3,4,3,1,2