diff --git a/algo/core/fasta.cpp b/algo/core/fasta.cpp
index 8a4c9f4c4edaa40e45047eadf561d6bb117169a4..5473bed9e91a4a148f3a781451cee3105216c523 100644
--- a/algo/core/fasta.cpp
+++ b/algo/core/fasta.cpp
@@ -59,7 +59,7 @@ void Fasta::add(istream &in, bool verbose) {
 }
 
 void Fasta::add(const string &filename, bool verbose) {
-  ifstream is(filename.c_str());
+  igzstream is(filename.c_str());
   if (is.fail())
     {
       throw invalid_argument(" !! Error in opening file: "+ filename);