diff --git a/setup_fof.py b/setup_fof.py
new file mode 100644
index 0000000000000000000000000000000000000000..22d5bf9dd5ef6bd52c4a6772f6ea5f0ce248735d
--- /dev/null
+++ b/setup_fof.py
@@ -0,0 +1,73 @@
+import os
+from pathlib import Path
+import shutil
+import glob
+import re
+
+##########################################
+# Select mass resolution and snapshotnumber
+##########################################
+mass_resolution_levels = ["M5"]
+snapshotnumber = 100
+##########################################
+
+localdir = os.getcwd()
+for mass in mass_resolution_levels:
+    os.chdir(os.path.join(localdir,mass))
+    for runfolder in glob.glob("Galaxy*/"):
+        ##########################################
+        # setting runfolder name and creating rerunfolder
+        ##########################################
+        runfolder_absolute_path   = os.path.join(localdir, mass, runfolder)
+        rerunfolder_absolute_path = os.path.join(localdir, mass+"_fofruns_snap%4.4i"%(snapshotnumber), "FOF"+runfolder)
+        Path(rerunfolder_absolute_path).mkdir(parents=True, exist_ok=True)
+        print (runfolder_absolute_path)
+
+        ##########################################
+        # change working directory to rerunfolder
+        ##########################################
+        os.chdir(rerunfolder_absolute_path)
+
+        ##########################################
+        # copy files into foffolder
+        ##########################################
+        shutil.copy2("../../fiducial_files/fof", "./")
+        shutil.copy2("../../fiducial_files/fof.yml", "./")
+        shutil.copy2(os.path.join(runfolder_absolute_path, "isolated_galaxy.yml"), "./isolated_galaxy_fof.yml")
+        shutil.copy2(os.path.join(runfolder_absolute_path, "output_%4.4i.hdf5"%(int(snapshotnumber))), "./")
+
+        ##########################################
+        # update yml file for fof run
+        ##########################################
+        string_filename = "  file_name:               output_%4.4i.hdf5"%(int(snapshotnumber))
+
+        f = open("isolated_galaxy_fof.yml", "rt")
+        data = f.read()
+        data = re.sub(r'^.*file_name.*$', string_filename, data, flags=re.MULTILINE)
+        data = re.sub(r'^.*basename.*$', '  basename:    fof_group_output  ', data, flags=re.MULTILINE)
+        f.close()
+
+        f = open("fof.yml", "rt")
+        datafof = f.read()
+        f.close()
+
+        f = open("isolated_galaxy_fof.yml", "wt")
+        f.write(data)
+        f.write(datafof)
+        f.close()        
+
+        ##########################################
+        # start swift for one timestep
+        ##########################################
+
+        os.system("./fof --stars isolated_galaxy_fof.yml")
+
+
+
+
+
+
+
+
+
+