Tank looks like it was just set-up not too long ago?
There's a few bad things i can see.
Coral with a Koran is a no no. Sand Sifting Star fish do not do good in a home aquarium unless you have a huge tank. They eat all edible life on and in the aquarium sand bed. Once it runs out of food, it will starve to death. Tank looks newly set-up for a Mandarin fish unless feeding on prepared foods. Like e55MD said Angel and Trigger will outgrow this tank.