SOUTH AMERICAN CICHLIDS.
Order Perciformes
Family Cichlidae
Subfamily ( Geophaginae )
Genus Acarichthys.
— Acarichthys heckelii [Muller & Troschel, 1848] — Threadfin Acara. Synonyms: Acara subocularis, Geophagus thayeri. (Eng. Elusive Cichlid, Finned Acara, Heckels Buntbarsch, Threadfin Acara, Cichlid). Northern Amazon basin, Colombia, Guyana, Brazil, Peru. 20-23 cm, in aquarium 15 cm. Main coloration is brownish-gray with a pinkish tint and small silvery sparkles, 9-11 longitudinal rows of golden dots on the body and two black transverse stripes through the eyes and in the area of the median spot, head is orange. Belly is pinkish. A black spot is located in the middle of the body. An indistinct black stripe runs from the eye downwards.
The last five rays of the dorsal fin, the end of the anal fin, and the outer rays of the caudal fin are filamentously elongated. The elongated rays of the dorsal fin and the upper filament of the caudal fin are red, the pelvic fins and the lower part of the anal fin are orange-red with a shiny blue border. Fins feature golden speckles. Males (besides size) differ from females by longer unpaired fins, brighter coloration, and a leaner body. The female is smaller, plumper, has less contrasting coloration and shorter fins.
Fish spend most of their time near the substrate (sand, fine gravel), happily sifting through it in search of food. They move the substrate around, so it should be fine-grained in aquariums. They may damage plants while landscaping their territory, so flora must be secured by covering the root system with heavy stones. Other tank decor elements also need secure fastening and can be chosen at discretion, along with areas planted with long-stemmed plants, driftwood, and caves.
During the breeding period, they are territorial; at other times, they are quite peaceful and can form a harmonious community with commensurable neighbors that lack a quarrelsome temperament. However, housing them with discus, angelfish (especially veil-tail forms), and small characins is not recommended. It is preferable to keep them in a small group of 5-6 individuals. They guard their territory; hiding places are needed. Sensitive to water chemical parameters and nitrogen presence.
They are omnivorous and voracious eaters of flakes, pellets, frozen, and live foods. Vegetable supplementation is desirable. Breeding is difficult. In nature, females dig burrows up to half a meter deep with three entrances. Males choose females with the best burrows, spawn with them, and then guard the territory around the nest. dH up to 15°; pH up to 8; T 25-30°C.
Genus Biotodoma.
— Biotodoma cupido [Heckel, 1840] — Cupid Cichlid. Synonym: Scophageophagus, Geophagus cupido, Acara subocularis. (Eng. Cupid Cichlid, Green Streaked Eartheater, Santarem). Middle Amazon basin, Brazil, Suriname, Guyana, Venezuela, Yari, Purus, Guaporé, Madeira, Ucayali rivers. 10 cm. Silvery-yellow with a black vertical stripe through the eye.
Near the end of the dorsal fin, above the lateral line, there is a large black spot. Tail has a white border. Dorsal and pelvic fins are elongated, caudal fin is fan-shaped. Dorsal fin is pale pink, anal fin is dark violet. Caudal fin is grayish-green. Males have blue iridescent lines on their cheeks.
Territorial and not very aggressive fish that should be kept in a group of 5 or more individuals. A dominant hierarchy forms within the group; in smaller numbers, weaker individuals may become targets of excessive aggression from the dominant fish. Aquarium should have plenty of hiding spots. Several large smooth stones are needed for the spawning area.
They dig and move the substrate in search of food, so it should be sandy in aquariums. Sturdy, hard-leaved plants with strong root systems should be planted in pots. Sensitive to changes in water conditions and pollutants. They should not be introduced into biologically immature aquariums. Fed with standard aquarium foods, including dry ones. dH 5-15°; pH 5.5-7.0; T 23-28°C.
— Biotodoma wavrini [Gosse, 1963] — Orinoco Eartheater. Synonym: Geophagus wavrini. (Eng. Orinoco Eartheater). Brazil, Colombia, Venezuela, Orinoco, Casiquiare rivers. 10-12 cm. Silvery-yellow with a black vertical stripe through the eye. Near the end of the dorsal fin, below the lateral line, there is a small black spot. Adult males are larger than females. Males may have elongated upper and lower rays of the caudal fin and elongated first rays of the pelvic fins.
Peaceful and, especially in the first days, extremely timid. They enter our aquariums only occasionally and solely as single specimens. They move the substrate, so it must be fine-grained in aquariums. T 24-28°C; pH 6.0-6.8; dH 3-8°.
Identification: Genus Biotodoma.
Biotoecus opercularis, Apistogrammoides pucallpaensis, Mazarunia mazarunii.
Crenicichla marmorata, notophthalma, regani, saxatilis. 
