diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index e0f2487..f0d15cb 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -45,7 +45,9 @@ jobs:
           
       - name: Install dadi and scikit-allel using conda.
         run: |
-          conda install dadi scikit-allel moments
+          conda install dadi scikit-allel
+          pip install Cython==0.29.18
+          pip install moments
 
       - name: Install GADMA and its dependencies.
         run: |