How to treat sick freshwater aquarium fishes(bacterial outbreak)

When I'm not working on my projects during the weekends or holidays, I breed freshwater fishes(mainly live bearers, cichlids, and nanofish) for some extra cash to fund my projects. I don't do this for a living but it really helps alot. Plus I get to enjoy observing their different breeding patterns and behavior. But there where some instances that their fishes get sick and mostly fishkeepers new to the hobby haven't got a single clue. And they blame me when their fish died a month after they bought it. So here is a step by step procedure on how to treat your pet fishes when they get sick.

First, isolate the sick fishes in a hospital/quarantine tank or any container provided it's big enough.

Next, physically observe the fish and determine each symptom because some species have unique diseases exclusive on their own kind (neon tetra disease, zebra danio disease). Checking on google the possible culprit of your pet's suffering. Once you determined it's an infection and not because of unstable water parameters, neglect in caring for your fish('this one you might go in denial but still you know deep down it was most likely your mistake or you still had slightly partaken in the events of your fish" sorry I'm just messin' with you), changes in temperature, stress, incompatible tank mates, uncycled aquarium, or using water directly from the tap which is loaded with chlorine, overstocked tank or tank is too small for the fishes(true for goldfish, monster fish, cichlids and plecos) then lets start the treatment. Me I don't usually use medications to treat my fishes unless necessary. I do salt baths which is really common for goldfish since this is one of the earliest form of fish treatment. Simply add a 1/4 teaspoon of salt per gallon in the tank and adding more every 3 hours while doing 50% water changes. Gradually adding more salt about 1/4 of a teaspoon every water change until it reaches 2 3/4 tablespoon of salt. Then change the water still every four hours adding more salt but decreasing the dosage until 1/2 of a teaspoon. When fish is now progressively getting better continue the frequent water change without the salt. You can now relax with the salt(unless the lights flicker). Many people have different methods but I find this more effective at killing off parasites and bacteria without using too lethal doses and this method of salt bath that doesn't put fish in some sort of shock. But there are species which can't tolerate salt so in those cases we use methylene blue or meds with copper and put medications in their food while doing 60% water changes, adding a heater and using a sponge filter. But word of advice even if you do this things properly there is no guarantee that your fish will survive as some diseases are untreatable.

More importantly in your main tank perform an 100% water change if the disease is of bacterial or microbial origin to prevent spreading of the disease to other fishes especially if you have more than one tank there is a possibility of cross contamination. Wash the plants and decorations under tap water and rinsing them with dechlorinated/treated water. Clean the entire tank if necessary assuming it has infected more than three. Quarantine the healthy ones and observe them if they might show symptoms in the following days or the next two weeks. To be sure put methylene blue in their water while recycling thier tank. Refill your tank with water and using cycled filter media jumpstart your main tank by dropping few pieces of fish food. After one week acclimate your fishes to the temperature of the main tank. Reintroduce the fishes(including the once sick fish) into the tank without letting much of the water to get into your tank.