diff --git a/public/app/plugins/panel/graph/threshold_manager.ts b/public/app/plugins/panel/graph/threshold_manager.ts
index f0bc7d62499..dcebc45c1e7 100644
--- a/public/app/plugins/panel/graph/threshold_manager.ts
+++ b/public/app/plugins/panel/graph/threshold_manager.ts
@@ -216,12 +216,6 @@ export class ThresholdManager {
           break;
         }
         case 'custom': {
-          if (!threshold.fillColor) {
-            threshold.fillColor = 'rgba(255, 255, 255, 1)';
-          }
-          if (!threshold.lineColor) {
-            threshold.lineColor = 'rgba(255, 255, 255, 0)';
-          }
           fillColor = threshold.fillColor;
           lineColor = threshold.lineColor;
           break;
diff --git a/public/app/plugins/panel/graph/thresholds_form.html b/public/app/plugins/panel/graph/thresholds_form.html
index 99e2f530c8d..075b4824d28 100644
--- a/public/app/plugins/panel/graph/thresholds_form.html
+++ b/public/app/plugins/panel/graph/thresholds_form.html
@@ -23,7 +23,7 @@
         <label class="gf-form-label">Color</label>
         <div class="gf-form-select-wrapper">
           <select class="gf-form-input" ng-model="threshold.colorMode"
-                  ng-options="f for f in ['custom', 'critical', 'warning', 'ok']" ng-change="ctrl.render()" ng-disabled="ctrl.disabled">
+                  ng-options="f for f in ['custom', 'critical', 'warning', 'ok']" ng-change="ctrl.onThresholdTypeChange($index)" ng-disabled="ctrl.disabled">
           </select>
         </div>
       </div>
@@ -73,4 +73,4 @@
       </button>
     </div>
   </div>
-</div>
\ No newline at end of file
+</div>
diff --git a/public/app/plugins/panel/graph/thresholds_form.ts b/public/app/plugins/panel/graph/thresholds_form.ts
index 4f480873d5b..08acd887559 100644
--- a/public/app/plugins/panel/graph/thresholds_form.ts
+++ b/public/app/plugins/panel/graph/thresholds_form.ts
@@ -1,5 +1,6 @@
 import coreModule from 'app/core/core_module';
-
+import config from 'app/core/config';
+import tinycolor from 'tinycolor2';
 export class ThresholdFormCtrl {
   panelCtrl: any;
   panel: any;
@@ -56,6 +57,19 @@ export class ThresholdFormCtrl {
       this.render();
     };
   }
+
+  onThresholdTypeChange(index) {
+    // Because of the ng-model binding, threshold's color mode is already set here
+    if (this.panel.thresholds[index].colorMode === 'custom') {
+      this.panel.thresholds[index].fillColor = tinycolor(config.theme.colors.blueBase)
+        .setAlpha(0.2)
+        .toRgbString();
+      this.panel.thresholds[index].lineColor = tinycolor(config.theme.colors.blueShade)
+        .setAlpha(0.6)
+        .toRgbString();
+    }
+    this.panelCtrl.render();
+  }
 }
 
 coreModule.directive('graphThresholdForm', () => {