Betta Tank Scum

Question
Hello Lynda!
I recently asked some questions about getting a betta for my dorm. I finally got him about a week ago, and I am really enjoying him! You weren't kidding when you said they have great personalities and that I would get attached! I do have one concern though. Unfortunately, because of space I had to settle for a 2.5 gallon aquarium. I know they really need 5 gallons, and I plan on moving him as soon as I can. Last week some white, filmy, scum substance started to appear on the top of his tank. I assumed this was because it was getting later in the week and getting time to change his water. I changed his water yesterday (one week after his purchase) using a gravel syphon. I also scrubbed the sides of the tank with an acrylic aquarium brush. However, this morning I noticed that the filmy substance was back, along with some brown scum along the inside of his tank that I never noticed before. I used a net to skim the surface, and it helped slightly. Do you have any ideas what could be causing the scum? I did a little bit of research, and I found out that the film can be a result of left over food. I feed him small amounts 2-3 times a day , and I make sure he always eats all of his food. Could the scum be left over from last week, as some water remained in the gravel as a result of using the syphon? Is it better to completely empty the tank each week and scrub it out with hot water and rinse the gravel? Will he be ok for another five days until his weekly water change? Also, he is pretty active most of the time, but sometimes will rest on the bottom of the tank for a couple of minutes. Is this normal/healthy behavior? Thank you so much!

Answer
Hi Hannah,
It is better to clean his tank by taking the betta out, and rinsing the tank out with warm water, until you know there is no food left at the bottom or in the gravel.  I would not wait, because food, and waste, can quickly bring bad bacteria to a tank.  It would be okay for you to do this now, and not chance him getting sick.
The film you are seeing sounds like a film that happens when bettas blow their nest.  If he is blowing his nest, then you know that this film is due to the betta's blowing.  I know this is kind of yucky, and sometimes we must change all of the water twice a week if it gets too bad.
Bettas like to rest on leaves, which is why it is a good idea to buy him a little silk plant, and also a little toy they can go through.  It is normal for a fish to rest.  They do not swim all of the time.
Yes we do get attached to this little fish, it amazes me how clever they are!!
Enjoy you little friend.
Lynda