diff --git a/bin/filter-hits-to-fasta.py b/bin/filter-hits-to-fasta.py
index <HASH>..<HASH> 100755
--- a/bin/filter-hits-to-fasta.py
+++ b/bin/filter-hits-to-fasta.py
@@ -23,11 +23,11 @@ if __name__ == '__main__':
 
     # Args for the JSON BLAST and FASTA files.
     parser.add_argument(
-        'json', metavar='BLAST-JSON-file', type=str,
+        'json', metavar='BLAST-JSON-file', type=str, nargs='+',
         help='the JSON file of BLAST output.')
 
     parser.add_argument(
-        '--fasta', metavar='FASTA-file', type=str,
+        '--fasta', metavar='FASTA-file', type=str, required=True,
         help='the FASTA file of sequences that were given to BLAST.')
 
     parser.add_argument(
filter-hits-to-fasta to take many json files