How many fish can i put into a 45 gallon 168 litres tank?
Discus will not do well with all those other fish in the tank. Many people refuse to believe this, which is one of the reasons there are so many dead discus. You could keep up to four discus in a 45-gallon tank, assuming you maintain excellent water quality, but not with all those other fish. Neon tetras are the favorite food of angelfish, which is probably why you started out with 5 neons and now have 1. You didn’t say what kind of gouramis you have, but if they are big enough to swallow the neons, they probably will, too. I wouldn’t say your tank is at maximum stocking yet, but you need to pay attention to which fish will live together without killing each other. If you want to add more fish, I would add more swordtails or more gouramis.