What's the black spots on my goldfish?

fish is slow laying on bottom of tank.
small flat black spots on top of head

black spot/black smudge?

we have no snails in the tank

please give help. for each piece of advice I will answer 2 of your questions.

thanks.

Hi,

Most commonly, black spots on goldfish are actually burn wounds from ammonia spikes. Over-crowding, poor water conditions and over-feeding can lead to ammonia burns and persistent ammonia spikes are lethal to the fish. There is also a black-spot disease caused by snails. This is more common in ponds but if you purchase your goldie from a fish store where snail infestations are prominent, this could be the source of your problem. A salt dip is recommended and frequent water changes necessary. There is no over-the-counter medication for this disease.

Hi. I also bought 3 goldfish a few months ago and they were doing great until I put in some water conditioner and bacteria enhancer. All of my fish got black smudges within 5 days! One of the fish was completely covered in black. It has been a week since it happened and for no reason the smudges are dissapearing. 2 Fish have none and the bad one is slowly getting better. It is the wierdest thing! There is some info on black smudge on the internet, but noone knows the cause or cure. Hope this helps a bit... I know I didn't really give you what you asked for, but... it is a mystery!