Flowerhorn Introduction to the Tank

Naveen asked 3 months ago

Dear Mr. Yashwant,
I am planning to buy a flowerhorn and introduce him into the tank
I have aerated my tank, used anti-chlorine, two teaspoon of aquarium salte and used heater with new water for the past 2 days. Will this be sufficient to introduce the fish?
Secondly, my first flowerhorn died all of a sudden after it contracted white spots and also Hexamitis. I have completed drained out previous water and cleaned the filters and power filter. As a precaution yesterday I have also put in a tablet of Metronidazole in the tank to erradicate any bacterial infections. Please advice if this is enough to avoid the previous bacteria affecting the new fish?