diff --git a/.github/workflows/test-cockatoo.yml b/.github/workflows/test-cockatoo.yml
index 8802ea6b..ee8c7e1c 100644
--- a/.github/workflows/test-cockatoo.yml
+++ b/.github/workflows/test-cockatoo.yml
@@ -20,7 +20,6 @@ jobs:
           environment-file: cockatoo.yml
           python-version: ${{ matrix.python-version }}
           auto-activate-base: false
-          mamba-version: "*"
           channels: conda-forge,bioconda,defaults
       - run: |
           conda info