I don't know if you can tell how tiny his tail is. I can never get a good picture of him. My plan as of now is to clean his tank tomorrow and put in some salt and hope for the best.
By the way it is a 2 gallon tank with a heater, no filter. I clean his tank once a week, that is I change a little more than 50% of the water. I use Prime and I feed him Top Fin, 3 pellets twice a day.