Zebra Danio With Mouth That Never Closes

[classicx10]

When i first got my 55 gallon, after it was cycled i bought some danios, i couldnt pass up the deal of 99 cents CDN for them. I got them home and got them in the tank. I noticed this one little guy, is mouth wide open. So i couldnt believe it, I never thought he would live, I checked him every day and watched him as he fed. He rams the food and it breaks up into small pieces and just swims right into the food. You can see his gills moving as he swallows. Just wondering if anyone knows why hes like that? Hes months old and does not have any diseases.

 

[CezzaXV]

Could be a birth deformity.

 

[classicx10]

i was thinking that. but was also wondering if he may have been sick one time, it looks brown around the edges of his mouth, so i thought maybe he had like a mouth rot or something and was treated before i got him.