Can anyone tell me whats going on with my child's toe?

[Toeto]

Started off about a week ago, noticed a small line going across the nail, steadily started to look more and more like this. It doesn't bother him at all but definitely doesn't look right either.

He hasn't banged it so far as I know (I'm with him nearly all the time!)

Anyone?

Fungus under the nail?

Fungus infection, get a spray from the chemist.

Has he banged it at some point? Looks exactly like my sons does every time its about to fall off (the nail not the toe!)