Reasons for prolonged and failed spawning

We experimented a bit with some spawning situations and noticed that the followings can cause fail spawning. Make sure your bettas do not have these conditions, otherwise you'll just watch them fail miserably....

1. female is too large. this one is pretty obvious, they may be eager, but if she's too large, there won't be any successful spawning. 3 conditions can come out of this: 1) female drops eggs 2) your male gets very tired and stop making bubbles 3) both get very stressed and no longer want to spawn
2. starving bettas. can you do anything when you are starving? your bettas can't either! how do you know your bettas starving? if you feed them on spawning tank, and they rush off to pick the foods, then you know they're starving!
   
3. water temperature too high or too low. not in the mood, they won't do it
4. no bubbles. some females are very picky, no bubbles, no spawning! some males are silly, they only care of chasing females but pretty useless on making bubbles. you may get spawning by scooping bubbles from other males, just to get them going; however, be very careful for incapable males, if they can't keep the building the bubbles, even when spawning happens, the egg/fry won't survive the critical 1 or 2 days of hatching.
5. you are ugly! some bettas are also picky about their partners. if they are not attracted to each other, then they'll ignore the existence of the other.
6. you scare the sh*t of me! if female is too small, compared to the male, and he is very macho and aggressive, the female may ended up hiding at all times. the male will brutalize her, but her trauma is not helping her on "doing it". if you let this to continue, 3 things can happen: 1) she'll die beaten by male 2) she hides forever and never wanted to spawn with any males ever again 3) male gets tired and this may lower his self-esteem, he thinks he's ugly and not attractive ;)
7. existence of other bettas in spawning tank. depending on whether they are accustom to other bettas or not, most of the time they won't share the tank with other fish. some times you get spawning happening, if you have nice anchor places for the male (and the female is attractive to him). community tank spawning is good experience. you'd be surprised, other bettas won't eat the fry, if they're well fed. mixing bettas with other types of fish is not good, the fry will just become sushi treat for some....
8. inexperience pair. as with any survival techniques, experience in spawning is a must. while most bettas will do just fine, there always are some that can't even get the technique correct. younger bettas have this tendency, so avoid spawning them too young. sometimes you see the males to be incapable, sometimes it's the female. typical problem is the position of the male and/or the female during wrapping. the female needs to be inserting herself with head a bit pointing upward and caudal tail pointing downward. same thing with male. if both males and females start off the wrapping flat horizontal, then they need to get to the angle position right away, otherwise the male can't wrap that tummy properly.
9. sub-optimal environment. your tank is too small, too large? you have that vibration next to the tank coming from pump? disco betta with very loud speaker next to it? very bright light shining to the tank at 24/7? foul water? at any rate, if your bettas aren't happy with their environment, you won't get spawning either.
   

If you notice that your bettas fall into the above situations, then you better off separating them and recondition for the next time.