Goose falling over and acting drunk

[TheKirad]

My almost 2 months old gander acts drunk has problem with balance
It started today
Idk what more to add
He is on niacin and other vitamins supplements, has constant acces to water to drink and container to swim in and constant acces to feed
I'm treating his angel wing on which he broke his feather which bleeds a bit from his falling over
Any advice?

 

[JacinLarkwell]

Did he get into anything poisonous or fermenting? I read a story about a chicken who ate an orange in the compost pile and got sick

 

[TheKirad]

I think he did.
I found some mold under his drinking dish. I recently replaced it with plastic container and since it's like 30° Celsius during the day, the water became infested with mold.
I replaced it with his old dish (metal bowl) and gave him clean water.
I also mixed a charcoal with water and injected it into his beak so his stomach gets clean

I'll wait until tomorrow to see if it helps