diff --git a/bin/pyenv-sh-activate b/bin/pyenv-sh-activate
index d01d0f1..d6b0d35 100755
--- a/bin/pyenv-sh-activate
+++ b/bin/pyenv-sh-activate
@@ -245,7 +245,20 @@ if [ -z "${PYENV_VIRTUALENV_DISABLE_PROMPT}" ]; then
   case "${shell}" in
   fish )
     if [ -z "${QUIET}" ]; then
-      echo "pyenv-virtualenv: prompt changing not working for fish." 1>&2
+      cat <<EOS
+functions -e _pyenv_old_prompt              # remove old prompt function if exists. 
+                                            # since everything is in memory, it's safe to
+                                            # remove it.
+functions -c fish_prompt _pyenv_old_prompt  # backup old prompt function
+
+# from python-venv
+function fish_prompt
+    set -l prompt (_pyenv_old_prompt)       # call old prompt function first since it might 
+                                            # read exit status
+    echo -n "(${venv}) "                    # add virtualenv to prompt
+    string join -- \n \$prompt              # handle multiline prompts
+end
+EOS
     fi
     ;;
   * )
diff --git a/bin/pyenv-sh-deactivate b/bin/pyenv-sh-deactivate
index 5a98142..8362494 100755
--- a/bin/pyenv-sh-deactivate
+++ b/bin/pyenv-sh-deactivate
@@ -187,7 +187,15 @@ esac
 
 case "${shell}" in
 fish )
-  :
+  cat <<EOS
+# check if old prompt function exists
+if functions -q _pyenv_old_prompt
+  # remove old prompt function if exists.
+  functions -e fish_prompt
+  functions -c _pyenv_old_prompt fish_prompt
+  functions -e _pyenv_old_prompt
+end
+EOS
   ;;
 * )
   cat <<EOS
diff --git a/test/activate.bats b/test/activate.bats
index 1379228..9c1fc67 100644
--- a/test/activate.bats
+++ b/test/activate.bats
@@ -138,7 +138,18 @@ EOS
 deactivated
 set -gx PYENV_VIRTUAL_ENV "${PYENV_ROOT}/versions/venv";
 set -gx VIRTUAL_ENV "${PYENV_ROOT}/versions/venv";
-pyenv-virtualenv: prompt changing not working for fish.
+functions -e _pyenv_old_prompt              # remove old prompt function if exists. 
+                                            # since everything is in memory, it's safe to
+                                            # remove it.
+functions -c fish_prompt _pyenv_old_prompt  # backup old prompt function
+
+# from python-venv
+function fish_prompt
+    set -l prompt (_pyenv_old_prompt)       # call old prompt function first since it might 
+                                            # read exit status
+    echo -n "(venv) "                    # add virtualenv to prompt
+    string join -- \n \$prompt              # handle multiline prompts
+end
 EOS
 
   unstub pyenv-version-name
@@ -164,7 +175,18 @@ set -gx PYENV_VERSION "venv";
 set -gx PYENV_ACTIVATE_SHELL 1;
 set -gx PYENV_VIRTUAL_ENV "${PYENV_ROOT}/versions/venv";
 set -gx VIRTUAL_ENV "${PYENV_ROOT}/versions/venv";
-pyenv-virtualenv: prompt changing not working for fish.
+functions -e _pyenv_old_prompt              # remove old prompt function if exists. 
+                                            # since everything is in memory, it's safe to
+                                            # remove it.
+functions -c fish_prompt _pyenv_old_prompt  # backup old prompt function
+
+# from python-venv
+function fish_prompt
+    set -l prompt (_pyenv_old_prompt)       # call old prompt function first since it might 
+                                            # read exit status
+    echo -n "(venv) "                    # add virtualenv to prompt
+    string join -- \n \$prompt              # handle multiline prompts
+end
 EOS
 
   unstub pyenv-version-name
@@ -239,7 +261,18 @@ set -gx PYENV_VERSION "venv27";
 set -gx PYENV_ACTIVATE_SHELL 1;
 set -gx PYENV_VIRTUAL_ENV "${PYENV_ROOT}/versions/venv27";
 set -gx VIRTUAL_ENV "${PYENV_ROOT}/versions/venv27";
-pyenv-virtualenv: prompt changing not working for fish.
+functions -e _pyenv_old_prompt              # remove old prompt function if exists. 
+                                            # since everything is in memory, it's safe to
+                                            # remove it.
+functions -c fish_prompt _pyenv_old_prompt  # backup old prompt function
+
+# from python-venv
+function fish_prompt
+    set -l prompt (_pyenv_old_prompt)       # call old prompt function first since it might 
+                                            # read exit status
+    echo -n "(venv27) "                    # add virtualenv to prompt
+    string join -- \n \$prompt              # handle multiline prompts
+end
 EOS
 
   unstub pyenv-virtualenv-prefix
@@ -263,7 +296,18 @@ set -gx PYENV_VERSION "venv27";
 set -gx PYENV_ACTIVATE_SHELL 1;
 set -gx PYENV_VIRTUAL_ENV "${PYENV_ROOT}/versions/venv27";
 set -gx VIRTUAL_ENV "${PYENV_ROOT}/versions/venv27";
-pyenv-virtualenv: prompt changing not working for fish.
+functions -e _pyenv_old_prompt              # remove old prompt function if exists. 
+                                            # since everything is in memory, it's safe to
+                                            # remove it.
+functions -c fish_prompt _pyenv_old_prompt  # backup old prompt function
+
+# from python-venv
+function fish_prompt
+    set -l prompt (_pyenv_old_prompt)       # call old prompt function first since it might 
+                                            # read exit status
+    echo -n "(venv27) "                    # add virtualenv to prompt
+    string join -- \n \$prompt              # handle multiline prompts
+end
 EOS
 
   unstub pyenv-virtualenv-prefix
diff --git a/test/conda-activate.bats b/test/conda-activate.bats
index 7469d83..452f6e3 100644
--- a/test/conda-activate.bats
+++ b/test/conda-activate.bats
@@ -70,7 +70,18 @@ deactivated
 set -gx PYENV_VIRTUAL_ENV "${TMP}/pyenv/versions/anaconda-2.3.0";
 set -gx VIRTUAL_ENV "${TMP}/pyenv/versions/anaconda-2.3.0";
 set -gx CONDA_DEFAULT_ENV "root";
-pyenv-virtualenv: prompt changing not working for fish.
+functions -e _pyenv_old_prompt              # remove old prompt function if exists. 
+                                            # since everything is in memory, it's safe to
+                                            # remove it.
+functions -c fish_prompt _pyenv_old_prompt  # backup old prompt function
+
+# from python-venv
+function fish_prompt
+    set -l prompt (_pyenv_old_prompt)       # call old prompt function first since it might 
+                                            # read exit status
+    echo -n "(anaconda-2.3.0) "                    # add virtualenv to prompt
+    string join -- \n \$prompt              # handle multiline prompts
+end
 EOS
 
   unstub pyenv-version-name
diff --git a/test/conda-deactivate.bats b/test/conda-deactivate.bats
index 905c7e5..7145fa8 100644
--- a/test/conda-deactivate.bats
+++ b/test/conda-deactivate.bats
@@ -82,6 +82,13 @@ if [ -n "\$_OLD_VIRTUAL_PYTHONHOME" ];
   set -gx PYTHONHOME "\$_OLD_VIRTUAL_PYTHONHOME";
   set -e _OLD_VIRTUAL_PYTHONHOME;
 end;
+# check if old prompt function exists
+if functions -q _pyenv_old_prompt
+  # remove old prompt function if exists.
+  functions -e fish_prompt
+  functions -c _pyenv_old_prompt fish_prompt
+  functions -e _pyenv_old_prompt
+end
 if functions -q deactivate;
   functions -e deactivate;
 end;
diff --git a/test/deactivate.bats b/test/deactivate.bats
index e6d366d..ed9e9b2 100644
--- a/test/deactivate.bats
+++ b/test/deactivate.bats
@@ -225,6 +225,13 @@ if [ -n "\$_OLD_VIRTUAL_PYTHONHOME" ];
   set -gx PYTHONHOME "\$_OLD_VIRTUAL_PYTHONHOME";
   set -e _OLD_VIRTUAL_PYTHONHOME;
 end;
+# check if old prompt function exists
+if functions -q _pyenv_old_prompt
+  # remove old prompt function if exists.
+  functions -e fish_prompt
+  functions -c _pyenv_old_prompt fish_prompt
+  functions -e _pyenv_old_prompt
+end
 if functions -q deactivate;
   functions -e deactivate;
 end;
@@ -251,6 +258,13 @@ if [ -n "\$_OLD_VIRTUAL_PYTHONHOME" ];
   set -gx PYTHONHOME "\$_OLD_VIRTUAL_PYTHONHOME";
   set -e _OLD_VIRTUAL_PYTHONHOME;
 end;
+# check if old prompt function exists
+if functions -q _pyenv_old_prompt
+  # remove old prompt function if exists.
+  functions -e fish_prompt
+  functions -c _pyenv_old_prompt fish_prompt
+  functions -e _pyenv_old_prompt
+end
 if functions -q deactivate;
   functions -e deactivate;
 end;
@@ -279,6 +293,13 @@ if [ -n "\$_OLD_VIRTUAL_PYTHONHOME" ];
   set -gx PYTHONHOME "\$_OLD_VIRTUAL_PYTHONHOME";
   set -e _OLD_VIRTUAL_PYTHONHOME;
 end;
+# check if old prompt function exists
+if functions -q _pyenv_old_prompt
+  # remove old prompt function if exists.
+  functions -e fish_prompt
+  functions -c _pyenv_old_prompt fish_prompt
+  functions -e _pyenv_old_prompt
+end
 if functions -q deactivate;
   functions -e deactivate;
 end;
@@ -307,6 +328,13 @@ if [ -n "\$_OLD_VIRTUAL_PYTHONHOME" ];
   set -gx PYTHONHOME "\$_OLD_VIRTUAL_PYTHONHOME";
   set -e _OLD_VIRTUAL_PYTHONHOME;
 end;
+# check if old prompt function exists
+if functions -q _pyenv_old_prompt
+  # remove old prompt function if exists.
+  functions -e fish_prompt
+  functions -c _pyenv_old_prompt fish_prompt
+  functions -e _pyenv_old_prompt
+end
 if functions -q deactivate;
   functions -e deactivate;
 end;
@@ -333,6 +361,13 @@ if [ -n "\$_OLD_VIRTUAL_PYTHONHOME" ];
   set -gx PYTHONHOME "\$_OLD_VIRTUAL_PYTHONHOME";
   set -e _OLD_VIRTUAL_PYTHONHOME;
 end;
+# check if old prompt function exists
+if functions -q _pyenv_old_prompt
+  # remove old prompt function if exists.
+  functions -e fish_prompt
+  functions -c _pyenv_old_prompt fish_prompt
+  functions -e _pyenv_old_prompt
+end
 if functions -q deactivate;
   functions -e deactivate;
 end;