it is either dying of deadly fungi or just getting old
it is living in the water that is not the right temperature or it might be dying if its a female 90% it might be giving birth.
it means their sick
Yes they do.
it is starting to die.
Koi fish Koi fish
There are many ways in which scales assist a fish. The easiest one to explain and probably the most accurate to answer your question is that the scales are smooth and provide an aerodynamic facade, which helps them swim more efficiently.
Koi fish can live in almost any country. Koi are thought to be originally from Japan. Many people have outdoor fish ponds in which Koi are the dominant fish.
Fish naturally loose their scales, but if your fish are loosing many scales at once, its not natural. Goldfish may loose their scales if they are stressed. If you get another fish, try medicating the tank with something like MelaFix for a while to prevent that from happening.
a fish, a koi carp
because it is fish
Koi are a type of specially bred carp.
Nope they sometimes eat there eggs
Koi fish usually have two eyes.
The Japanese for Koi is nishikigoi.