betta not building bubble nest

Question
I have set up my 5 1/2 gallon tank with plants and sponge filter and heater in corner. I have half stirofoam cup tapped in the tank. Female in her container beside cup. He flares at her and contstantly goes back under cup, but wont build a nest. at times he sits beside her and she beside him. He goes all around her and always back under the cup but wont build or nest or start to. She has a vivid white spot under her and she is plump. He wont eat much but she does. Should i release her to see if he starts or get a different male? The tank is at 80 degrees.

Answer
Are you sure there isn't something happening with the filter getting to the bubble nest even under the styrofoam?  Hmmm, Do you know this male betta or is he new to your betta family? Did you get him at a petstore? He could be too old to breed which is often the case with pet store bettas. Either this or he might not be in the greatest health. It sounds like you have researched betta breeding as you did not just throw him in a tank with her like a lot of un researched breeders so good job for that! You might want to go ahead and take the male out and see if you can assess what might be wrong with him. Unless he is a pet store betta and in that case if there is nothing wrong with him, he might just be too old. Though I have seen once put into the housing next to the female many male bettas do stop eating. To be honest I'm unsure why this happens. In my experience eating has always picked back up after a day of not seeing his female and being back in his own home. So you can try that and then try him again after he has had a chance away from your female for a while and see if he is in a better bubble nest mood :) or choose another betta if you like. Hope this helps some. Let me know if you need anything else :)