Since it is in a small container, is there a filter in there? Just asking. I will tell you how I clean my little tanks. I scoop up some of their water into a little cup or a ziploc bag and then scoop him out into that cup or bag. If you use a bag, make sure there is air in the top so that he can breath, i usually use a cup fisrt so that he is not in the bag for any longer than he needs to. He gets very sad, but cleaning is needed. Make sure that if you scoop him out in a cup, you put some type of lid on the cup for him, as he will jump out on the counter. With me having so many bettas, i have one of those big water jugs that i keep water in, you know those ones that companys get bottled water in. Anyway, i keep water in there for their cleaning. After they are out of the tank, i take it all out and rinse it all clean, no soap of any kind, i do 100% water changes on unfiltered little tanks. After cleaning all of the stuff, i refill it with treated water. I then put betta in a ziploc bag and float him for 15 minutes on top. I then net him and put him back in his tank. Throwing out the water in the ziploc. I am sure there are other ways to do this, but that is how i do it. Good luck, Sandy