Help Needed For Apistogramma Diplotaenia!

[marle]

Guys,

Need your help with regards to my Diplo, its a she, and i think she might have a problem, her tail is being clamped together. Despite her problem, she has been eating well and swimming well but i think that is only temporary, and it won't be good if i delay till her problem gets worse!

I am not unsure as to what medication to administer and what brand. Have read up, it might be internal bacteria or fin rot. Please give me some advices asap! Below are the pictures of her.

HELP! Thank you.

[SCOPE]

i guess this is caused by water issue...you just recently change water?
For safety sake, separate the male from the female