betta tank and companions

Question
Hi, my 15 year old goldfish recently passed away so my betta, George, inherited a 20 gallon tank after living 2 months in a 2 gallon tank. The 20 gallon seemed pretty empty with just George, so i got a school of 10 neon tetras since my boyfriend had 2 bettas in the past (not at the same time)that lived well with tetras. They all seem to do well together so far for the past 4 days, and I was told by someone that my male betta could also live with 2 female bettas in a tank my size, but I had always thought that bettas would also fight each other, male or female, just males were worse. George is a male Crowntail if that makes a difference, and I am very fond of him so I dont want to put him in danger. Also, I have started experimenting with live plants since he seems to like the frill plant I got to hide in. Should I get him live plants or just plastic, and if so are there plants that bettas really like or that are bad? Also, would George be safe with any female bettas, or should he just have the neon tetras for friends and nothing else? I know that he would nip most other fish that have tails. I use easy balance for the pH and keep the tank at about 78-81 degrees with its heater. Thank you for your time.

Answer
Hi Shawna,
Never put female bettas in with a male betta.  Bettas are loners, and as you know, Siamese fighting fish.  Males or females will not mix.  They will kill each other.  Just the sight of each other brings them stress, and stress fish get sick.  Females do not get along so well either.  Sooner or later the dominate one will attack the others.  In my experience with bettas, I am confident in telling you, that they never get along. ( I have bred, and had bettas for a very very long time.)  Few fish get along with the betta.  Sometimes a school of cory fish, platys, some loaches, fresh water shrimps, and dwarf plecos may be added, but there is no guarantee, as each Betta has his own personality.  If your Betta is getting along with neons, I would leave it at that...maybe add 4 cory catfish.  I would like to mention that neons live in acidic soft water.  If you see any problems with the neons, it will most likely be the PH.  Do not add salt with neons.  Test your water every week to see if your water chemistry is perfect.  This means no ammonia, no nitrite, and nitrates must be low.  You can buy these test kits at your pet store, or Walmart, or you can have it tested at the pet store.  These test kits are always handy to have.  Ammonia, and nitrites are the number one killer of fish.  You may know this, since you have kept fish for 15 years!  Congratulations!  I love to read things like this.
I am not a plant expert, so would prefer you ask an expert on this matter.  We have some on the team who could guide you.  
Never use products for the PH.  They do more harm than good.  Driftwood is a natural, and better choice to bring your PH down.  Wash it well, and let it sink in a pail of water, rinsing it everyday for a week or so, until the tint is out of it.
I hope this helps.
Lynda