diff --git a/src/core/de.evoal.approximative.density/src/main/java/de/evoal/approximative/density/ea/fitness/DensityBasedFitness.java b/src/core/de.evoal.approximative.density/src/main/java/de/evoal/approximative/density/ea/fitness/DensityBasedFitness.java
index 7c36e1cc58e5453dc06f9c67e108a5b455a44de4..8f321592312c4d128513eb3f68434b97b03608c0 100644
--- a/src/core/de.evoal.approximative.density/src/main/java/de/evoal/approximative/density/ea/fitness/DensityBasedFitness.java
+++ b/src/core/de.evoal.approximative.density/src/main/java/de/evoal/approximative/density/ea/fitness/DensityBasedFitness.java
@@ -61,7 +61,7 @@ public abstract class DensityBasedFitness extends FitnessDecorator {
 
         kind = LanguageHelper.lookup(config, "kind");
         exponent = LanguageHelper.lookup(config, "exponent");
-        rootExponent = LanguageHelper.lookup(config, "root_exponent");
+        rootExponent = LanguageHelper.lookup(config, "root-exponent");
 
         // TODO Check this section if it is really correct in all cases.
         final List<FunctionCombiner> mappings = surrogate.getMappings();