Hi, I've had a look round the forum and couldn't find the answer to my question, but if it is a re-post I apologise! My son has a ruby shark in his tank, which has been happy enough until a week or so ago, when we noticed it's changed colour from silver to black, and it's eyes are 'bugging' out. It's always seemed ok in the tank, and claimed a hollow skull as its home as soon as it was put in. We haven't changed the food or the times between cleaning or introduced any new fish for at least 2 months. It's my sons fave fish, so I'd just like some advice on whether this is normal or not. Thank-you!