Have I Got This Right About Water Changes?

[b.c.f.c]

right getting a betta soon and ive been doing my reasearch.But im a bit puzzled on water changes.from what i have read i think it goes like this.............if you keep your betta in a 5 gal or less 100%water changes should be done and then a dechlorinator (sp) should be added.But if you have a bigger tank than a five gal you should have a small filter and 20% water cahnges done weekly.

Is this right as i dont want to get my betta thinking im doing everything right and then everything going wrong.
im thinking of getting a 5 gal so should i have a filter or do 100%weekly water changes?thx for any info it would be much appriciated and thx for all the info ive got so far off other threads.

 

[Mr.September15]

I heard that only tanks less that 3Gallons should have complete water changes. The tanks like 1 gallon, 2 gallon, 1.5, 2.5 etc. should have complete water changes twice or once a week. My 3 gallon has a filter in it already so I dont think too much waste can build up but you should do a 10-20% water change, Even though you dont have a filter....O yeah almost forgot you have to add dechlorinator. Look on the bottle for instructions on how much usually a capfull for a 1/2 gallon but check anways.

Good Luck!