A peaceful, slow-moving nano reef favorite with a green-yellow face, dark midband and a red-spotted rear, looking as if dressed in mismatched pajamas. Hardy, easy to feed and easily bred, it is an excellent beginner marine fish kept in small groups.
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Educational only. KinStation content is reviewed by licensed veterinarians but cannot replace an in-person exam. Always consult a licensed veterinarian or board-certified specialist for diagnosis, treatment, or any decision affecting your pet's health.
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Western Pacific, from Java and Indonesia to Papua New Guinea and Fiji
Climate
🌴 Tropical
Water type
🌊 Marine
Family
Apogonidae
Genus
Sphaeramia
Part of the Cardinalfish
Peaceful, often nocturnal mouthbrooding reef fish (family Apogonidae) that hover in groups; many are hardy, reef-safe, and readily bred in the aquarium.
From the minimum an animal needs to be kept humanely, up to the ideal setup. Bigger is almost always better — minimums are floors, not targets.
Photo coming soon
Minimum
Small school reef
30 gal / 110 L reef (school of 4+)
Sphaeramia nematoptera is a peaceful slow-swimming schooler. Keep 4+ to dilute pair aggression; reef-safe, gentle flow, varied frozen foods.
Photo coming soon
Recommended
Mature reef community
55 gal / 200 L+
Larger group (5–8) in a peaceful reef. They hover near rock overhangs by day, feed at dusk. Mouthbrood eggs — a tame captive-breeding target.
Ideal
Dim mixed reef
90 gal+ / 340 L+ dim reef
Spacious mixed reef with sheltered overhangs, low-flow zones, and a stable school. Natural breeding and mouthbrooding visible regularly.
Coughdrop12 / CC BY-SA 4.0 (Wikimedia Commons)
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Photo coming soon
Egg
Fish eggs are small, translucent spheres, often laid in clutches on plants, substrate, or in a nest — or carried/brooded by a parent in livebearing and mouth-brooding species. A dark eye spot and the curled embryo become visible inside as development progresses.
Photo coming soon
Fry
Newly hatched fry are tiny and semi-transparent, frequently still carrying a yolk sac that fuels them before they feed freely. They lack full fin structure and adult coloration, staying near cover until they can swim and forage on their own.
Photo coming soon
Juvenile
Juveniles look like miniature adults but with developing fins and muted or different markings; many species shift pattern and color as they mature. Growth is rapid at this stage given clean water and steady feeding.
Adult
Adults show the species' full size, finnage, and mature coloration, and are sexually mature. Many fish develop sex-specific differences in size, color, or fin shape, which can intensify during breeding.
Habitat & enclosure
Keep a small shoal in a reef tank of at least 115 L (30 gal); a larger tank suits bigger groups. Maintain 24-27 C (75-81 F), pH 8.1-8.4, salinity 1.023-1.025 SG, dKH 8-12. Provide low to moderate flow and live rock with overhangs or branching corals to hover among; subdued or standard reef lighting is fine, as this is a nocturnal-leaning, low-energy fish.
Substrate
Fine sand with live rock that includes shaded overhangs and ledges, or branching corals, where the fish can hover during the day.
Equipment & setup
Standard reef filtration with a protein skimmer, a heater, and gentle to moderate flow (strong flow stresses these weak swimmers). Reef LED lighting is suitable; the fish does not need intense light.
Diet
Carnivore that feeds at dusk and night on zooplankton and small crustaceans. In the aquarium it readily takes frozen mysis, enriched brine, finely chopped seafood and meaty pellets; feed once or twice daily, ideally toward evening. Easy to feed and not a fussy eater.
Behavior & temperament
Very peaceful and fully reef-safe; it hovers in loose groups and is largely sedentary by day. Keep a small group rather than a lone individual, and avoid boisterous or predatory tankmates that will outcompete or eat them. Mixes well with other calm reef fish such as gobies, firefish and clownfish.
Health
Hardy but susceptible to marine ich and velvet if not quarantined, and to Brooklynella and Uronema in stressed shipments. Maintain good water quality and feed well. Slow, deliberate movement means it can be bullied by fast feeders.
Tips, DIY & hacks
A great mouthbrooding breeding project: the male incubates the eggs in his mouth, and pairs spawn readily in the home aquarium. Buy a group so a natural pair forms. Drip-acclimate and quarantine; feed at dusk to suit its natural rhythm.
