Moderately aggressive species, especially when breeding. Keep it with other Central American cichlids only in a tank large enough to allow each species space to form an adequate territory. Shoals of peaceful mid and upper-water dwelling species are probably the best choice for tankmates. In its natural waters it can be found living alongside livebearers such as Poecilia and Alfaro spp., plus characins, including Astyanax aeneus, and freshwater gobies.
The male is larger and more brightly coloured, particularly when in spawning condition. The female has a dark spot in the dorsal fin, and when spawning her lower half turns black with a large copper-coloured spot.
Not fussy and will accept most foods. Live and frozen? bloodworm, Artemia, chopped prawn/shrimp, etc., should form a good proportion of the diet, though good quality dried foods may also be used. Try to ensure the fish receive some vegetable matter in the form of proprietary products with added. Spirulina or fresh blanched greens, peas or similar.
https://www.seriouslyfish.com/species/archocentrus-myrnae/