Fin rot or bacteria?
Hi, Iím 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 itís fine! Iíve 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 donít 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!