Name of disease: Not a disease in itself but secondary infections can set in following any physical damage to fish.

Occurrence: Common, affects all types of freshwater fish
Symptoms include: Obvious scale loss (not one or two scales but whole patches), split or ragged fins, grazes, scratches, lesions or wounds on body, fins or mouth, bleeding, damaged or missing eye(s), fish is listless and hides or sits on bottom.
Caused by: Rough handling, recent importation/transportation, fighting, fin-nipping, spawning, banging into something sharp in tank or pond, recent parasite infestations (e.g. Ich can leave physical damage on body).
Treatment: Remove affected fish to hospital tank and maintain perfect water quality. Add salt to a .3% solution to 1) prevent secondary bacterial / parasitical or fungal infections occuring at site of damage, and 2) to help fish control its osmoregulation. Add a small amount of Melafix to promote healing. Keep a close watch on fish to check for signs of deterioration or secondary infection (if wounds worsen or more wounds appear then underlying bacterial activity must be suspected - treat with antibiotic medication). Feed with a high quality nutritious food, such as krill. If wounds are deep, hold fish gently in a wet cloth (soaked in old tank water) and dab wounds gently with iodine, mercurochrome, neosporin or dilute TCP solution and release back into tank.
Precautions: Medications may affect the cycle so monitoring water quality during treatment is essential. Fish will be stressed from the damage so may take some time to return to normal behaviour.

great post..
thanks..
jus in time as one of my fish got hurt after crashing into my siphon tube and got a scratch.. well, that clumsy fish.. suddenly he jus decided to come near me when I was cleaning out and I was worry I might accidental hurt him thus I duck.. gosh, n he got shocked and darted right into the siphoning thingy and got scratch!! lucky not so serious.. jus a scratch, losing a strip of scales...

Your poor fishie. If it's only a scratch and a few scales lost though then he should heal very quickly, especially as I know you always keep your water quality excellent. I'd just keep an eye on him for a few days to make sure the area doesn't get infected and the other fish aren't picking on him. There's probably no need to do anything else, but you might like to add a bit of Melafix to speed up healing.