Breeding Rainbows.

I have three types of Rainbows Red Rainbows 2 Male and one Female, Turquoise one Male and one Female and Melanotaenia Praecox, Neon Rainbows4 male and 2 Female. My pair of Turquopise Rainbows are in a 29 gallon and they breed all the time. The Red ones are also in another 29 gallon and I have tried every thing to get them to breed and they don't. The Neon Praecox are in a 20 gallon tall and they will not breed either. The water stats are the same, they are in planted tanks with live plants. I feed them Brine Shrimp, Blood Worms, vegetable dried food. I have a mop in each tank. Does anyone have any suggestions.