diff --git a/src/eva2/server/go/operators/terminators/FitnessConvergenceTerminator.java b/src/eva2/server/go/operators/terminators/FitnessConvergenceTerminator.java
index 60f0624b..6803bd9f 100644
--- a/src/eva2/server/go/operators/terminators/FitnessConvergenceTerminator.java
+++ b/src/eva2/server/go/operators/terminators/FitnessConvergenceTerminator.java
@@ -123,7 +123,7 @@ Serializable {
 	}
 
 	protected void saveState(PopulationInterface Pop) {
-		oldFit = Pop.getBestFitness();
+		oldFit = Pop.getBestFitness().clone();
 		oldNorm = PhenotypeMetric.norm(oldFit);
 		popFitCalls = Pop.getFunctionCalls();
 		popGens = Pop.getGeneration();