Just to let you know, I tried putting some neon's in with Boris my Betta, who has been with me for 5 weeks now. He's in a 6 gallon tank and I keep thinking he must be lonely in there, so after some research I thought, I know I'll put my remaining 3 neon's in with him (did have 5 but have recently lost 2).
He went beserk, chased them round the tank like a loon for about 3 minutes, really flared up, he calmed down when they hid in the cave, but the minute he caught sight of them, he just went after them, so I hooked them out and put them back in my main tank, and have now decided perhaps he doesn't mind his own company!!!!
Although he's still really mad at me, all the times I've gone near the tank even to feed him, he's flared at me!!
P