diff --git a/pkgs/top-level/aliases.nix b/pkgs/top-level/aliases.nix
index 66fa444e0e7..d1a7543ac15 100644
--- a/pkgs/top-level/aliases.nix
+++ b/pkgs/top-level/aliases.nix
@@ -421,6 +421,7 @@ mapAliases ({
   skrooge2 = skrooge; # added 2017-02-18
   skype = skypeforlinux; # added 2017-07-27
   skydive = throw "skydive has been removed from nixpkgs (2019-09-10)";
+  slack-dark = slack; # added 2020-03-27
   slic3r-prusa3d = prusa-slicer; # added 2019-05-21
   slurm-llnl = slurm; # renamed July 2017
   slurm-llnl-full = slurm-full; # renamed July 2017
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index d3fac637ca8..783c36cb1fd 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -20045,8 +20045,6 @@ in
     });
 
   slack = callPackage ../applications/networking/instant-messengers/slack { };
-  slack-theme-black = callPackage ../applications/networking/instant-messengers/slack/dark-theme.nix { };
-  slack-dark = pkgs.slack.override { theme = slack-theme-black; };
 
   slack-cli = callPackage ../tools/networking/slack-cli { };