I'm trying to cycle a new 20 gallon aquarium with one small goldfish that my son won at a carnival. It's been a few weeks and no matter what I do, I cannot get the ammonia to come down or the tank to cycle. I was doing 2.5 to 3 gallon water changes every day to every other day and ammonia just kept going up. Finally it got so high and the fish was not well so I decided to vacuum the gravel and changed between 50 to 75% of the water. Norman, the fish, finally started swimming and coming out of his house after I cleaned it and the ammonia was down to .25. But then within 2 days it was back up past 4 or even higher, then today the water got really cloudy which i know is just a bacterial bloom from the big water change. I've been adding ammo lock every couple days but I'm still concerned because he has more and more black burn spots from the ammonia. prior to the big change change there was little to no nitrites and same for nitrates. What am I doing wrong? I really don't want this poor fish to suffer. I want him to thrive and I'm just so worried about him. What do I do?