Hi! It's great that you upgraded him to a bigger tank. I'm sure he's thrilled!!!! For the water changes, it depends. Is it filtered?
I have a 3 gallon filtered tank and I do one 50% water change with gravel vaccum and one 25% just water change every week because ammonia builds up fast in those tanks. Because with just one 50% with vaccum a week, it would test positive for ammonia before the week was over. Granted it wasn't a high % of ammonia but still.
If it's not filtered I would do two 50% water change a week.
As for decorations, if you want something cheap that betta usualy love, go for the terracota pots. They make great hiding spot and they are aquarium safe. Or you can just use a coffee mug that you have at home. I prefer silk plants to plastic plants because there's less chances of ripping your betta's fins.
Also, if you are like me and DON'T have a green thumb at all but still want some live plants that your fish is going to love, go for the mossball. They are easy to take care of and the fish love it.
Last edited by Gen2387; 02-09-2012 at 02:38 PM.