Hey and welcome
there are a few issues that you have raised. Peps are harder to sex as mooo said, and unlike the common bristlenose, females peps more often than not have bristles and they do take a bit longer to become different. the thing is that the females only have bristles on their top lip, if the birsltes begin to run up the snout then its def a male. Best thing to do is to get a piccy for us to look at.
Breeding a father an a daughter is not recommended. It is a 1/8 chance that the offsrping will have the same genes and even though this sounds like a low possability, when you consider that there are thousands of genes, you can see the scale of the issue. I know a lot of people do inbreed them but you do risk low spawn rates and high fry mortality.
You need a heater! while they breed in cooler water than normal you only drop the temp for a few days, and even then its only by a few dregrees, from about 26 degrees to 22 degrees.
You do need to do a bit more research. Breeding bristlenose, especially peppermints, is something that you need to look into. There are lots of threads on here looking at breeding so have a look through them, this one is this one from our faithful leader
Either that or have a look through my ebook, PM me for a link.
peps are harder to breed than the commons so don't be surprised if it takes a while for both yourself and them to get into the swing of things
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