Be sure to maintain at least 78F.....
Um, no. I have siquia convicts and we just roll with the local temps moderated by 130 gallons of water in the tank. Temps in Nicaragua range from the 50s to the 105s F -- but the water will never be that cold or that hot in the lakes and rivers. The big thing with the females I've had is that they want the boys to be bigger than they are. He's the defense muscle. He courts her by fanning his body so the water he moves hit her lateral line. He might mate with the smallest female in the tank; she won't mate with the smaller of two males.
In the spawns that I raised, the girls start larger but when their bellies start showing red, the males will have a growth spurt.
Don't know about the nigrofasciatus convicts -- but they're from further north than the species here.
