How often...55 gals

[Friendlyfishies]

How often and what % of would you have to change in a 55 gallon tank for a single betta, live plants, a small school of white cloud minnows and a snail?

[LebronTheBetta]

What about the filter? Due to the small amount of stock, there won't be as much minerals used and I think the DOCs (dissolved organic compounds) won't be that high.. A 25% change per week should be sufficient.