Firemouth pairing length

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At what length/age do firemouth cichlids start pairing up. I have 4 I believe are 2 males and 2 females. They are around 2-3 inches. There is one (the largest) very aggressive one that because of that I think might be male, but it is very drab and doesn't have any fin extensions, making me think it is female, while one of them has very nice color and fin extensions, and another one has little color but fin extensions, and the fourth one isn't colorful has no fin extensions (the smallest) but has two spots rather than one on one side of its body. Also the most colorful one is a much darker gray than the others, why is this?

[Aeonflame]

They start breeding at around 4 inches

[><))>WBW<((><]

Cool, I noticed two spot and colorful one seem interested in each other.