diff --git a/src/ic_generator.cc b/src/ic_generator.cc
index c243f6c..cfd9003 100644
--- a/src/ic_generator.cc
+++ b/src/ic_generator.cc
@@ -542,7 +542,13 @@ int run( config_file& the_config )
         music::ilog << std::endl
                     << ">>> Computing ICs for species \'" << cosmo_species_name[this_species] << "\' <<<\n" << std::endl;
 
-        const real_t C_species = (this_species == cosmo_species::baryon)? (1.0-the_cosmo_calc->cosmo_param_["f_b"]) : -the_cosmo_calc->cosmo_param_["f_b"];
+        // const real_t C_species = (this_species == cosmo_species::baryon)? (1.0-the_cosmo_calc->cosmo_param_["f_b"]) : -the_cosmo_calc->cosmo_param_["f_b"];
+
+        real_t C_species = (this_species == cosmo_species::baryon)? (1.0-the_cosmo_calc->cosmo_param_["f_b"]) : -the_cosmo_calc->cosmo_param_["f_b"];
+
+        if( species_list.size() == 1 ){
+            C_species = 0.0;
+        }
 
         // main loop block
         {