Hi all,
They are not at all aggressive, but they are black water fish, so they need very clean, acidic, low conductivity water (extremely soft, really below 50 TDS, and ideally below 10) and below pH 6., they also like the water warm (above 27oC). I'm not sure which L numbers you could keep them with, although a small Hypancistrus or Panaque species would be a possibility, they don't like a lot of flow, but they are all right, best in fact, in very heavily filtered water.
Even at pH6 they are unlikely to spawn successfully, and you may need to get down to below pH 5 - pH4.5 with 0dGH, at these buffering and pH levels water quality maintenance, even though they are small cichlids, is easier in a bigger volume tank, and with very low stocking.
They need lots of cover a sand substrate, ideally both leaf litter and plants, live food and fairly subdued light, normally they are kept with Pencil fish as dithers, or a small black water tetra or even dwarf Cories. BBS., Grindal worms and Daphnia are the usually suggested food, but I think they will try and eat anything that wriggles, because black water fish have to eat what ever is available. Java moss, Java fern, Ambulia, Water sprite, Cryptocoryne are the sort of plants you need, they are open spawners and will use a piece of bog wood or an Amazon Sword leaf.
I was quite tempted, and after advice I set up a tank for them, but even using rain water, peat filtration and some acidic leaf mould in the substrate I just couldn't keep the pH low enough, I tried to source Dicross maculatus, (which comes from less extreme conditions), but couldn't and eventually I got some less demanding Apistogrammas instead.
The great Larry Waybright (Apistomaster) breeds them, and he said:
"My own experience with breeding this species spans 4 decades. I have found them easy to spawn but generally harder than most Apistogramma spp. to get viable eggs and the fry are extraordinarily sensitive to any decline in water quality. Females often eat their spawn but the greatest success in breeding them always occurs when the female takes good care of the fry. Good luck, everyone. I still consider them harder to breed and raise than wild Discus. I almost always have D. filamentosus because wild fish are so cheap in the USA and they are among the most beautiful of SA Dwarf Cichlids."
cheers Darrel