diff --git a/changelog.md b/changelog.md
index 3bdb520..18393ad 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,6 @@
 # 0.4.0.0
 
+* Remove instances `Foldable` and `Traversable`, they are too dangerous to diverge.
 * Add `HalfWord` and `ThirdWord` types,
   change types of `toZCurve`, `fromZCurve`, `toZCurve3`, `fromZCurve3` accordingly.
 * Add `throughZCurveFix` and `throughZCurveFix3`.
diff --git a/src/Data/Chimera/Internal.hs b/src/Data/Chimera/Internal.hs
index 357e15e..de36452 100644
--- a/src/Data/Chimera/Internal.hs
+++ b/src/Data/Chimera/Internal.hs
@@ -103,10 +103,6 @@ newtype Chimera v a = Chimera {unChimera :: A.Array (v a)}
   deriving
     ( Functor
       -- ^ @since 0.2.0.0
-    , Foldable
-      -- ^ @since 0.2.0.0
-    , Traversable
-      -- ^ @since 0.2.0.0
     )
 
 -- | Streams backed by boxed vectors.