diff --git a/nixos/modules/services/networking/ssh/sshd.nix b/nixos/modules/services/networking/ssh/sshd.nix
index c0ad9e17c413..a7617d02c185 100644
--- a/nixos/modules/services/networking/ssh/sshd.nix
+++ b/nixos/modules/services/networking/ssh/sshd.nix
@@ -195,12 +195,14 @@ in
         default =
           [ { path = "/etc/ssh/ssh_host_dsa_key";
               type = "dsa";
-              bits = 1024;
             }
             { path = "/etc/ssh/ssh_host_ecdsa_key";
               type = "ecdsa";
               bits = 521;
             }
+            { path = "/etc/ssh/ssh_host_ed25519_key";
+              type = "ed25519";
+            }
           ];
         description = ''
           NixOS can automatically generate SSH host keys.  This option
@@ -323,7 +325,7 @@ in
 
                 ${flip concatMapStrings cfg.hostKeys (k: ''
                   if ! [ -f "${k.path}" ]; then
-                      ssh-keygen -t "${k.type}" -b "${toString k.bits}" -f "${k.path}" -N ""
+                      ssh-keygen -t "${k.type}" ${if k ? bits then "-b ${toString k.bits}" else ""} -f "${k.path}" -N ""
                   fi
                 '')}
               '';