Hurt guppy

[Mangoguayaba]

I bought 6 fish for my 30 gal tank 3 guppies and 3 cherry barbs 3 days ago

This night after doing a water change I noticed that one of my guppies has a bent tail and is clenching his tail fin

I am 100% sure that his tail wasn't bent yesterday

Can I do anything to help him without hurting him more, and if I cant help him will he be able to live like this

 

[Delapool]

Some if they last a week will live a long time ime. How is he doing?