I used to breed bettas, so I will chime in.
#1)... I woke up one day to eggs floating at the top of the breeding tank I had, no bubble nest.. but the surface tension was enough to keep the eggs boyant. The male replaced the eggs if they fell, raised several full grown bettas from that hatching. There wasn't much surface movement, so the eggs were just fine.
#2) The female will point head down/up and go "dead in the water" looking for a few minutes during the mating process. She may develop some vis sable stripes on her sides too. (neat to watch)
#3) I always used Atison's betta PRO for conditioning my pairs about 2 - 3 weeks prior to breeding, and after to help healing. I use nothing else, and they helped females develop eggs faster, mature faster, and also conditions the male to top breeding form, and builds them both up for the process that can hurt them physically.
#4) Adding Betta Spa (almond leaf extract) or something that releases "tannins" in the water
helps promote breeding and holds bubblenests together. Attison's also makes this in a easily dispensable dose product.
OH.. NO.. I am NOT a Rep for them either! I just like their stuff, and it has proven excellent over the counter use for bettas.
#5) I use a small piece of "lab tube" Styrofoam (small 2" cut square that has small holes in it), or you can use the styro cup like you are. It all keeps the eggs warm and moist and helps the bubble nest stay together, protects it from air and movement.
#6) To feed the fry, I always used a microworm culture. Brine shimp eggs had shells that fry can choke on and "croak", so I saved feeding them a hatching of BS until they were about 10 days old. When I switched to the microworms for the newly hatched fry, no problems, and they just loved them like kids to candy.
#7) Be prepared to move your female to another container, or isolate her to heal after it is all said and done. She'll need to rest and recover. I lost about 40% of my females after breeding. It can be a tough go on her, and infections are common after scales have been ripped off, etc, due to rough breeding process. You may have to treat her to prevent opportunistic infections if the female shows signs of physical damage.
This is just my experience. I wish you the best on your endeavors. It is a wonderful process.
