Barb changing or tail damage?

[AlexLbk]

My hystrix developed what looks like a skin cut right at the base of her upper barb. This barb has been there for at least 6 months and the one below that is already full grown.
I'm attaching pictures of what it looks like. Has anyone seen anything like that?

 

[oldfish]

Looks like it is getting ready to fall off.Normal stage they go through

 

[aquaman45]

yes normal process.
Be sure to remove the barb once it drops off, many a good ray has accidentally become impaled by the old barb, if it enters the vital organs it will prove fatal.
Don't want to lose a cracking Hystrix like that one.