You could maybe add a moss ball from petco or LFS
. Check the tank and fish it's stored in when you buy it, but maybe it would have some good bacteria on it to help you. People have posted to squeeze them good before putting them in your tank and the to squeeze and reroll them in your hands once a week.
Be gentle with a moss ball or it will break. I had one between bigger than a baseball and smaller than a softball and I would squeeze it like that and it finally broke, and I waited for a year to see if it would grow together, or make new balls, but no, so be very gentle if you get one. They are awesome, I just bought a new one this weekend! It is good to roll it around so it doesn't get flat, also, I use a (new, used just for aquatics) chop stick.