I have a small mixed-breed dog he is 5 years old. A few months ago we set up a fish aquarium, it is 50 gallons and full of fish. My dog is obsessed with the fish aquarium and will stare at it for hours and try to bite the fish (he only bites the glass and leaves scratches on it). I am afraid the fish are going to get stressed out and die. How can I distract him? We play games with him, walk him, run him, he has bones, toys, etc. But we have to occupy him all the time, any time he is not occupied he is sitting in front of the fish tank!!!

Any ideas? Thank you

Decide which is more important in your life - the fish or the dog.

put the fishtank in another room where your dog can't go?
put a fireguard round the tank to stop him getting so close?