80L is a very small aquarium for these fish, unless you have a separate and much larger aquarium to use as a grow out I would heavily recommend you avoid trying to breed them. This is before any trials such as trying to rehome potentially a couple hundred young cichlids. In that size aquarium you would likely end up with a spawn and the pair would kill off all of the others but down the line you might not even get the pair to coexist and could lose one of them most likely the female if there is a large size difference. I have a dozen firemouths growing out in two four foot aquariums atm and struggle to picture such a large fish living in so small of an aquarium with any success long term. If I was you i'd try to either sell them before you get into issues or trade them in for a smaller species, many true dwarf species would be far better options. Try to pick something that won't exceed more than a couple inches SL. What is your water chemistry at home and do you use RO, rainwater or any mix? Knowing what you have to work with will make if much easier to suggest alternative species.