I got home this afternoon to find smashed glass inside my tank,then noticed my ID shark has copped some nasty slices to his body,head and a 1'' slice just above his eye.Im pretty sure the culprit is my clownknife which i have busted chasing the big guy when the lights are off.Is it ok to add salt to help him recover? Is 1 tablespoon per 10 gallon ok?.Should i up the temp? At the moment the temp is 27 degrees celcius.The shark is 22'' long and is housed in an 8x2x2 with a 19'' giant gourami, 17'' clownknife and a 22'' freshwater eel.Ive had him for over 7 years and is my pride and joy.