Probably because they are just very territorial.
Beta fish do NOT like other fish, they may try to kill the other fish or get seriously injured by the other fish.So probably not.
no they dont usally like to be with others
It depends weather the fish like each other or not
These are tropical fish that like their water warm. Betta are best kept at 26 to 28 degrees Celsius.
If your fish is a fighting fish it will be still for most of the day and probably attack another fish who wanders into his "territory". Fighting fish often come in bright colours like red or blue. But some fish are just naturally aggressive and hurt or kill your other fish! {trust me I've experienced this } It's very important to know the difference between a aggressive fish and a fighting fish. If you still can't tell talk to your local pet store or talk to an expert.
No fish likes direct light. They hunt for other fish, so your lure should either sparkle or jiggle(to look like a wounded fish). Live bait should be very lively where possible
There are no do's or dont's. It all depend on the fish and the situation. Dont get me wrong, dont like poke a stick in the water and hope to catch anything, but other that that , it all depends on the fish and the place
None, they are dominant creatures you can rarely put them in a tank with another fish. Not sure about a female one with a male but still not best to be tried with. ;)
maybe you can put a non-aggressive fish that if physically provoked by the fighting fish it can defend itself. or fast moving fish like goldfish so it can outrun the fighting fish. when feeding your fishes they usually move quick, putting their mouths above water. however, the betta doesn't. and they can get easily annoyed when other fish bump them. so,I recommend the angelfish.
you put it in and if it seems like they are fighting then take it out. If it seems like they are humping each other, then unless you want a lot of baby goldfish, take it out.
There are no fighting fish that come from Japan. I think you are asking about the Siamese fighting fish (Betta splendens). They do naturally have a round stomach almost like a ball. That is their body shape.
A fish that is larger than the fighting fish itself, like a shark or ray, or even a large alligator gar. Other smaller fish though, unless they're the type that are careful to stay out of the fighting fish's way at all times, should not be put in with such a fish.