my lil betta :(

Question
Hi, i have a betta who was fine until 5 days ago. I have 63litre tank and he has been happily living with 2 balloon mollies, 2 panchax, 3 hi fin platies and 2 corys. I added 5 phantom tetras and a bulldog plec from a different store than where i got the other lot. He now has mouth rot and fin rot. He is very lethrgic and I have been adding KB fin rot and fungus control, he has made no improvement (got worse if anything) and I am worried that he is going to infect the other fish- I have no quarantine tank to put him in. Should I continue treating or put him out of his misery- I'm heartbroken ;(

Answer
Hi Francesca,
The cause of his fin rot is probably due to not quarantining your other fish. I would also test the water readings as bad water quality can cause fin rot. I would suggest moving your betta into a tank by himself because its not good to treat the other fish if they dont have any sort of disease.
Good luck!

Chloe.