diff --git a/src/ai/ga.js b/src/ai/ga.js
index 655df3d..3e7fc0d 100644
--- a/src/ai/ga.js
+++ b/src/ai/ga.js
@@ -2,7 +2,7 @@ const { maxBy, random, times, sample, sampleSize } = require('lodash');
 
 class Individual {
   constructor(genome) {
-    this.fitness = 0;
+    this._fitness = { value: 0 };
     this._genome = genome.map(gene => ({ value: gene }));
   }
   set genome(genome) {
@@ -13,6 +13,12 @@ class Individual {
   get genome() {
     return this._genome.map(gene => gene.value);
   }
+  set fitness(fitness) {
+    this._fitness.value = fitness;
+  }
+  get fitness() {
+    return this._fitness.value;
+  }
 }
 
 class GeneticAlgorithm {