Fin rot or bacteria?

[Mrsreah]

Hi, I’m fairly new to freshwater fish keeping. I have a 120l tank with four guppies, four small mollies, a plec, two Siamese algae eaters and five tetras. I think personally that the tank is overstocked but my husband thinks it’s fine! I’ve done a 25% water change and added a fin rot treatment yesterday, however today the fish looks worse with a red spot now on his tail. I don’t want the others to suffer the same thing. Could anyone offer some advice on what to do next? Water parameters are 0 nitrite and ammonia, 10 nitrate, pH of 7.2 and temp of 27c. Thank you!

 

[SteffeyJ]

Hello, have you ever seen any of the other fish tail nipping?? Could this be a possibility??

 

[Mrsreah]

Thank you for your reply, no I don’t see them getting bullied. Unfortunately this fish died so I’m now treating the tank.

 

[ErrorcodeJoe14]

It was probably getting fin nipped which causes stress and then died from the stress!