The umbrella dwarf cichlid, Apistogramma borelli, owes its common name to the large, sail-like dorsal fin, which becomes increasingly pronounced as the fish matures. There are a handful of forms, with the most commonly encountered being "Opal," "Blue," and "Yellowhead." Borelli are tolerant of cooler water temperatures than most Apistogrammas, and generally quite forgiving of water conditions, making them an excellent beginner's Apisto. In their natural habitat, like most Apistogramma , these fish come from soft, relatively acidic water, and these conditions may be required for successful spawning.
Umbrellas are reasonably peaceful fish, though they are territorial and will protect their favourite coconut shell, cave, or other structure. The males can be aggressive toward each other, especially during spawning. It is not unusual for a younger, 'subdominant' male to take on the colouration and appearance of a female to avoid aggression from the dominant male -- which can be frustrating for those who think they have a pair!
These fish mix well with other small, peaceful fish, including most tetras, small barbs and other cyprinids, and rainbowfish. Excellent top water additions would include many of the various small killifish, and especially hatchetfishes.