White Marks On Sharks Tail

[kris1978]

i have a large black shark and have just noticed it has greyish marks on its anal fin and its back tail, the greyish colour goes right through the fins, it doesnt look like whitespot or fungus, any ideas, here is a pic.
please help

 

[WILDER]

Size of tank in gallons or litres.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.

Greyish marks can be parasites to columnaris.
Any signs of flicking and rubbing against objects.
Or laboured breathing.
Any excess slime on body or gills.

 

[Colin_T]

it proably just scratched itself. Do a daily partial water change and gravel for a week and see how it goes. It should clear up by itself.