Bolivian ram

Water parameters

Tolerated range for this species. Aim for the middle of each band rather than the extremes.

Tank and habitat

Substrate: sand.

Behavior

Plant interaction: plant safe.

Feeding

Omnivore that feeds primarily on the bottom and in the lower midwater. Sinking pellets, frozen bloodworm, frozen brine shrimp, frozen daphnia, live blackworms, and baby brine shrimp are all accepted. Dry food is taken without trouble; wild-caught fish sometimes refuse pellets and flake at first but switch over with time. The species sifts the substrate for food, taking mouthfuls of sand and passing it through the gills to extract small organisms and plant matter (the behaviour the genus name 'small eartheater' actually describes), so a sand substrate matters more than it does for most community fish, and sharp gravel can injure the gills or get lodged. Two feedings a day. Live and frozen food brings out colour and conditions pairs for breeding.

Compatibility

• The hardy alternative to the German blue ram. Tolerates 22-26 C community temperatures rather than the 27-30 C M. ramirezi prefers, which makes it compatible with a much wider range of tankmates including tetras, rasboras, corydoras, and otocinclus
• Peaceful dwarf cichlid with mild territorial behaviour around resting and breeding spots. Much less aggressive than Apistogramma, kribensis, or convicts
• Adult cherry shrimp are usually ignored; shrimplets sometimes get eaten. Not a reliable choice for a dedicated shrimp tank
• Pairs defend a territory during breeding but the aggression is restrained. A community tank can usually accommodate a spawning pair without major disruption to other species
• Stop-and-go swim style and slow, deliberate feeding mean fast tankmates can outcompete the species at meals. Match with mid-paced peaceful fish

Origin and habitat

A small geophagine cichlid endemic to the upper rio Madeira basin in Bolivia and western Brazil, with records from the Mamore, Guapore (known as the Itenez in Bolivia), and the upper Orthon (its Tahuamanu and Manuripi tributaries). The type locality is a sandbank in the Rio Mamore just below the mouth of the Rio Guapore, near San Joaquin, Bolivia. Wild habitat is poorly documented but the species seems to live in slow-moving tributaries, marginal zones, oxbows, and lakes with sand or mud substrate, where it sifts the bottom for food. Linke and Staeck, who first imported the fish to Europe in 1985, reported that wild fish live solitary lives outside of breeding. Haseman described the species in 1911 as Crenicara altispinosa; it has since been moved through Microgeophagus (Axelrod 1971), Papiliochromis (Kullander 1977), and into the genus Mikrogeophagus as currently accepted. The alternative spelling 'Microgeophagus' and the species form 'altispinosa' both still circulate. The genus contains two recognised species in the trade (M. altispinosus and M. ramirezi, the German blue ram), with a third, M. maculicauda, described in 2022 from the Pindaituba River in Mato Grosso (previously the hobby's 'Two-patch' or 'Zweifleck' fish). The Mikrogeophagus name combines Greek mikros 'small' with the genus name Geophagus 'eartheater', and altispinosus combines Latin altus 'high' with spinosus 'thorny', a reference to the species's elongated dorsal fin rays. IUCN Least Concern. The Bolivian ram looks similar in profile to the German blue ram but reaches a noticeably larger adult size (up to about 9 cm, with reported males up to 8-9 cm and females smaller), lacks the blue iridescent fin and head markings of the ramirezi, and shows a more subdued grey-buff body with a black midlateral spot, a black bar through the eye, and red and yellow flushes on the fins. Sexing is hard: males are slightly larger and slimmer with longer outer caudal rays, but young fish are difficult to sex even for experienced keepers. The species has a characteristic 'stop-and-go' swim where it moves in short bursts and then hovers in place rather than coasting, which appears to be a feeding adaptation for not stirring up the substrate.

Breeding

A biparental open substrate spawner. Pairs form by themselves out of a group of young fish, and the best approach is to start with six to eight juveniles and let them sort out who pairs up. The pair selects a flat surface (rock, broad leaf, piece of driftwood, sometimes the aquarium glass), cleans it carefully, and digs a few shallow pits in the surrounding sand. The female lays the eggs in neat rows of five to eight at a time, with the male passing over each row to fertilise. Clutch is around 100 to 200 eggs (with reports up to 300). The female fans the eggs almost continuously while the male defends the perimeter; she swaps roles with him only briefly when she stops to eat. Eggs hatch in about three days. The parents then move the wrigglers in their mouths into one of the pre-dug pits and shuffle them between pits over the next several days. Fry become free-swimming around seven days after hatch and start on microworm, baby brine shrimp, and finely powdered fry food. First-time pairs eat their brood often enough that it should be expected; most pairs settle into reliable parents by the third or fourth attempt. The Bolivian ram has no specific spawning trigger beyond good food, clean water, and an undisturbed pair, and is genuinely much easier to breed than its more famous cousin.

Common problems

Hexamita (the parasite behind hole-in-the-head and head-and-lateral-line erosion in cichlids) shows up occasionally, especially on diets that lean too heavily on dry food; metronidazole and a varied diet with frozen and live food are the standard fix. Internal parasites brought in with new fish cause slow wasting; praziquantel handles most of these. The more common 'problem' is one of expectations rather than fish health: buyers used to the gaudier colours of the German blue ram are sometimes disappointed by the more muted greys, buffs, and tail-fin reds of the Bolivian. The trade-off works in the keeper's favour, though, since this is a hardier fish that handles community temperatures and parameter swings the ramirezi does not. Breeding pairs in a community tank cause minor disturbance rather than chaos, but very timid bottom-dwellers (pygmy corys especially) can still be stressed.

Bioload

Further reading

• How to cycle a fish tank
• Stocking ideas by tank size