Hello, I would recommend a double sponge filter for your ten gallon. The sponge is great for establishing bacteria and the gentle flow is perfect for a betta.
http://www.amazon.com/XY-2822-Double-Sponge-Filter-Aquarium/dp/B005VAFGKI
http://www.amazon.com/dp/B0009YJ4N6/ref=twister_B00DZF8YQE?_encoding=UTF8&psc=1
I love sponge filters because they really help out with breaking down waste and ammonia which are dangerous to fish. I actually had both this sponge filter and the Whisper 10i in my 10 gallon (bacteria colony:sponge filter, larger waste+water movement:whisper).
As for other decorations, live plants are the best, but beginners should start out with easy plants or live plants/silk plants combo. Avoid hard plastic plants that can injure your betta. I have betta hammocks for my fish and they love sleeping on them.
http://www.amazon.com/Zoo-Med-Laboratories-AZMBL20-Hammock/dp/B0027IZ6KW/ref=sr_1_1?s=pet-supplies&ie=UTF8&qid=1452534088&sr=1-1&keywords=betta+hammock
As for your heater, if it looks similar in size to the one you use in a 2.5 tank, it might not be powerful enough to heat a 10 gallon.
http://www.amazon.com/gp/product/B000OQO69Q?keywords=fish%20heater&qid=1452534176&ref_=sr_1_1&sr=8-1
And lastly, if you don't already have one, invest in a cave or other hiding place for your betta to make him feel more secure! Happy fishkeeping!
http://www.amazon.com/XY-2822-Double-Sponge-Filter-Aquarium/dp/B005VAFGKI
http://www.amazon.com/dp/B0009YJ4N6/ref=twister_B00DZF8YQE?_encoding=UTF8&psc=1
I love sponge filters because they really help out with breaking down waste and ammonia which are dangerous to fish. I actually had both this sponge filter and the Whisper 10i in my 10 gallon (bacteria colony:sponge filter, larger waste+water movement:whisper).
As for other decorations, live plants are the best, but beginners should start out with easy plants or live plants/silk plants combo. Avoid hard plastic plants that can injure your betta. I have betta hammocks for my fish and they love sleeping on them.
http://www.amazon.com/Zoo-Med-Laboratories-AZMBL20-Hammock/dp/B0027IZ6KW/ref=sr_1_1?s=pet-supplies&ie=UTF8&qid=1452534088&sr=1-1&keywords=betta+hammock
As for your heater, if it looks similar in size to the one you use in a 2.5 tank, it might not be powerful enough to heat a 10 gallon.
http://www.amazon.com/gp/product/B000OQO69Q?keywords=fish%20heater&qid=1452534176&ref_=sr_1_1&sr=8-1
And lastly, if you don't already have one, invest in a cave or other hiding place for your betta to make him feel more secure! Happy fishkeeping!