diff --git a/app/ecs/ecs.js b/app/ecs/ecs.js
index 8a47672..7485a94 100644
--- a/app/ecs/ecs.js
+++ b/app/ecs/ecs.js
@@ -178,7 +178,11 @@ export default class Ecs {
 
   deindex(entityIds) {
     for (const systemName in this.Systems) {
-      this.Systems[systemName].deindex(entityIds);
+      const System = this.Systems[systemName];
+      if (!System.active) {
+        continue;
+      }
+      System.deindex(entityIds);
     }
   }
 
@@ -384,7 +388,11 @@ export default class Ecs {
 
   reindex(entityIds) {
     for (const systemName in this.Systems) {
-      this.Systems[systemName].reindex(entityIds);
+      const System = this.Systems[systemName];
+      if (!System.active) {
+        continue;
+      }
+      System.reindex(entityIds);
     }
   }