Guppy tail rip

[mPhish]

Hi, one of my guppies has a rip in his tail from the end about 2/3rds of the way towards the base of his tail. He swims fine and everything. I was wondering what could have caused this, if it will heal on its own, or should I do something?
Yesterday I did a 20% water change with API stress coat, I used double because it says it helps heal fins and skin if you double amount (per amount of water).

 

[keegster803]

Can I see a pic of the guppy?


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[Fish_Fan]

What other fish are in the tank? Any sharp decorations?

 

[mPhish]

fish_fan 7 other male guppies and some rough fake coral?

 

[mPhish]

What other fish are in the tank? Any sharp decorations?

7 other male guppies and some rough fake coral
I think his tail is healing, thanks tho!