Fin Rot?!

Morning all.
I purchased 3 male endlers last week and all seem happy to be fair but there is one that has a fancier tail and it's frayed and I think it's getting worse.
When I got him there was already a bit of it missing but I think it's getting worse.
I see no white on the end of it either.
I have 9 harlequin rasboras
3 male endlers
4 nerite snails
2 ammano shrimp
And a panda garra.
I've attached a photo so hopefully you wonder dull people can give me some help.
Oooo water paremeters are
Cl2.       0
Ph.        7.6
Khd.      4/5
Ghd.        8
No2.         0
No3.        20
Ammonia.0
26°c
Thank you in advance

Water quality looks good, so keep up the good work on regular water changes, etc, to ensure it stays like this.

I don't see any particular problem, but am not very familiar with endlers.  That said, the best way to ensure they're ok is optimum water quality, and it can take some time for fins to grow back if there is a problem, so I think just keep monitoring the situation and comparing photos from week to week.