ok
my tank is about 1 0r 2 gallorns i have two mollies one black and one silver(white)
my fish white mollie's tail is red here is a picture.

please help me im a begginer

and my fish poo is red

How often do you clean the tank?

once a month
i separeted the fish in hospital tank
i put salt
and put 10 Mg of Minocycline

since u say its 1 or 2 gallons, there should be alot of waterflow, yet in the pic i dont see any. maybe its too blurry but, i have to ask. do u have a filter? oh and also, how often do u do water changes and gravel siphonings?, how often do u feed them and about how many flakes ( if flakes ) per fish?

and by tank cleaning, im sure glaive meant what i just said, as completely cleaning the aquarium, can cause recycling ( the basteria cycle which keeps water stable gets out of whajk and it tries to fix itself, leaving the water out of whack. )