Apistogramma Macmasteri Apistogramma macmasteri

Quick Stats

Tank Setup

The Apistogramma macmasteri is the colourful Colombian apisto — a bright yellow body, a red-orange face, and spectacular filaments streaming off the first few spines of the male's dorsal fin. It sits between cacatuoides and agassizii in the genus's beginner-to-advanced spectrum: not quite as bulletproof as borellii, but far more forgiving than hongsloi or agassizii, and visually one of the most striking dwarf cichlids you can put in a 20 gallon. If you've kept cacatuoides or borellii successfully and want a fish that pops harder under the lights without jumping to the deep end of the genus, macmasteri is the species I steer people toward.

Maintain water parameters within: temperature 24–28°C, pH 5.5–7.0, hardness 2–10 dGH. Macmasteri comes from the upper Meta River drainage in Colombia, where the water is soft and tannin-stained but not extreme — the parameters fall between cacatuoides (pH 4.5–6.5, GH 1–8) and borellii (pH 5.5–7.5, GH 2–15). Captive-bred fish (which is almost certainly what you are buying) will live and breed at pH 6.8 and GH 8 without complaint. I run my colony at 26°C, pH 6.4, GH 5 — soft but not extreme, straight RO cut 1:1 with tap — and the males colour up like someone painted them. Do not push temperature above 28°C sustained; bacterial infections spike fast in warm, soft water, and macmasteri is more vulnerable to heat stress than borellii.

Set up the tank with a fine sand substrate (1–2 mm pool filter sand or play sand, 3–5 cm deep), driftwood, leaf litter (Indian almond leaves), and dense planting along the back and sides. The non-negotiables are caves: one cave per female, plus one spare. Coconut shells with a 1.5 cm entrance hole, half-buried flower pots turned on their side, or slate stacks all work — the entrance must be just large enough for the female to enter and the male to be excluded. Apistogramma are sifters; they will sand-sift all day looking for food, so gravel disqualifies a tank. Macmasteri males are also jumpers when spooked, especially first-generation wild-caught stock — a tight-fitting lid is non-negotiable on this species.

Tank Mates

Apistogramma macmasteri are peaceful for cichlids — until they spawn. A guarding female will attack any fish that comes within a body-length of her cave, including fish three times her size, and macmasteri females are slightly more aggressive defenders than borellii — closer to cacatuoides in intensity. Plan tank mates around the spawning reality, not the resting state.

Compatible tank mates include: tetras that tolerate 24–28°C (Ember Tetra, Rummy-nose Tetra, Diamond Tetra, Cardinal Tetra), pencil fish (Nannostomus), Corydoras (especially dwarf species like habrosus or pygmaeus), Otocinclus, and peaceful mid-water schooling fish. I keep my macmasteri colony with a school of Ember Tetras and a group of Corydoras habrosus; the tetras act as dither fish that signal “no predators above”, and the corys occupy the bottom without competing for the caves. Avoid housing with other Apistogramma species (they will hybridise or fight), large aggressive cichlids, bottom-dwelling predators like Synodontis catfish, and any fish large enough to eat a 5 cm female. Macmasteri hybridises readily with cacatuoides in particular — never mix the two if you intend to breed either species.

The harem structure matters: one male with two to three females per territory, in a 20 gallon long with broken sight lines. Two males in a 20 gallon will fight — sometimes to death, especially when a female is in spawning colour. If you want multiple males, you need a 4-foot tank (40 gallon breeder or larger) with visual barriers between each male's territory. A sexed group of 1M:3F is the standard starter colony; the females will establish a pecking order among themselves, and the dominant female will spawn first. Macmasteri males are slightly less aggressive toward each other than cacatuoides males, but the one-male-per-territory rule still applies — the filaments on the dorsal are an invitation to fin-nipping from a rival male.

Diet & Feeding

Apistogramma macmasteri are micro-predators. In the wild they eat insect larvae, small crustaceans, and worms pulled from the sand. In the aquarium they accept frozen bloodworm, frozen brine shrimp, live blackworms, live baby brine shrimp, and high-quality micro pellets (I use New Life Spectrum Thera+A 0.5 mm or Fluval Bug Bites Cichlid Mini). Flake is accepted but not ideal — it does not trigger the hunting behaviour that keeps them active and coloured up. Of the common Apistogramma species, macmasteri is the most responsive to diet-driven colour change: a flake-only macmasteri is a pale yellow fish with a faint red wash on the shoulder; the same fish on a frozen-and-live diet for six weeks is a different animal entirely.

Feed small amounts twice daily. A female guarding eggs or fry will eat very little; do not panic if she refuses food for a week — this is normal. Target-feed with a baster or long tweezers; macmasteri learn to recognise their keeper and will take food from your fingers within a few weeks. The filaments on the male's dorsal grow back fuller and longer on a high-protein diet — if your male's dorsal looks stubby after shipping, six weeks on frozen bloodworm and live blackworm will fix it.

The colour payoff from a varied diet is dramatic, and it is the main reason macmasteri has a reputation as a “colour fish”. The two colour forms in the hobby — the standard “Red Shoulder” macmasteri (bright yellow body with a red-orange blush over the gill plate and shoulder) and the line-bred “Super Red” or “Superscale” form (where the red extends across the face, chest, and front of the dorsal, pushing the yellow toward the rear) — are not different species. They are selectively bred colour morphs of the same fish, and a low-quality diet will mute both forms to a washed-out peach. If you paid for Super Red stock, do not feed flake — you are paying for colour and then starving it.

Common Health Issues

The two conditions I see most in Apistogramma are Hexamita (intestinal flagellates) and bacterial gill disease. Hexamita shows up as white, stringy, buoyant faeces, weight loss despite feeding, and a sunken belly. Treat with metronidazole — either in food (250 mg per 100 g of food for 7 days) or as a bath (500 mg per 10 litres for 7 days, in a separate hospital tank). Bacterial gill disease shows up as rapid breathing, clamped fins, and a fish hanging at the surface; treat with a broad-spectrum antibiotic in a hospital tank and address the underlying water quality. Macmasteri is slightly more vulnerable to Hexamita than borellii — the same soft-water preference that makes it colourful also makes it susceptible — so I run a prophylactic metronidazole food course on every newly arrived macmasteri.

Ich is a constant threat because Apistogramma tanks run at 24–28°C, the upper end of the ich reproduction range. The standard heat-and-salt treatment is risky: pushing temperature to 30°C to defeat ich will stress your macmasteri and may trigger bacterial infections. I treat ich in Apistogramma tanks with formalin/malachite green (Rid-Ich or similar) at 75% of the label dose, holding temperature at 28°C. Copper-based treatments are toxic to dwarf cichlids — do not use them. Macmasteri's filamented dorsal is also a magnet for fungus if water quality slips; any tear in the fin tissue will fungus within 24 hours at nitrate above 30 ppm.

Prevention is straightforward: weekly 25–30% water changes with dechlorinated, temperature-matched water, no ammonia, no nitrite, nitrate below 20 ppm. Apistogramma tolerate nitrate worse than tetras — a tetra will shrug off 40 ppm nitrate, a macmasteri will lose colour, stop breeding, and become disease-prone. Quarantine new fish for four weeks in a hospital tank before adding them to a colony. Lifespan in good conditions is 3–5 years, with the upper end coming from cooler tanks (24–26°C) rather than the 28°C upper limit. Wild-caught macmasteri typically arrive carrying internal parasites; treat prophylactically and do not skip quarantine.

Breeding

Apistogramma macmasteri are cave-spawners and one of the easier dwarf cichlids to breed in captivity. The female initiates spawning: she picks a cave, turns bright yellow with black markings, and leads the male to the entrance. A typical spawn is 40–80 eggs, deposited on the roof or wall of the cave. The male leaves after spawning; the female tends the eggs exclusively. Macmasteri is one of the more reliable spawners in the genus — first-spawn females rarely eat their clutch, which is a common failure mode in cacatuoides and agassizii.

Eggs hatch in 48–72 hours at 26°C. The female will move the wrigglers to a pre-dug pit in the sand, then to another pit, then another — every 8–12 hours for the first three days. Once the fry are free-swimming (day 5–7 post-hatch), the female herds them around the tank in a tight school, gill-flaring and charging anything that approaches. The male guards the perimeter; in a harem setup, he will rotate between the territories of his females. Macmasteri females are attentive mothers and will hold the school together for 3–4 weeks — longer than cacatuoides, which typically lose the school after 2 weeks.

Feed the fry infusoria for the first three days, then graduate to live baby brine shrimp. They grow quickly on BBS — 1 cm in four weeks, sexable at three months, sexually mature at six months. The most common mistake is feeding flake or pellet too early; Apistogramma fry need live food for the first two weeks or they starve slowly. A single pair in a 10 gallon species-only tank will produce 30–50 survivors per spawn with no intervention beyond water changes. Breeding for colour forms is straightforward — Red Shoulder to Red Shoulder produces Red Shoulder; Super Red to Super Red produces Super Red; Red Shoulder to Super Red produces a mix, with roughly 60% Super Red phenotype and 40% Red Shoulder phenotype in the F1 generation, assuming a heterozygous Red Shoulder parent. Line-breeding for the Super Red form is well-established in the hobby — it took roughly a decade of selective breeding to fix the line, and the trait is now stable across generations.

Frequently Asked Questions