American flagfish guide

Common name: American flagfish
Scientific name: Jordanella floridae
Category: Freshwater fish
Group: North American killifishes
Environment: Freshwater and slightly brackish subtropical aquarium
Origin: Florida peninsula, United States
Care level: Intermediate
Adult size: Up to 6.5 cm total length
Expected lifespan: Multi-year; no dependable species-specific maximum was located, so plan permanent housing for at least several years rather than treating it as a short-lived algae-control animal.
Minimum housing: At least 75 litres for a pair; 120 litres or more for a group or community
Temperature: 18–24 °C
pH: 6.0–8.0
Hardness / minerals: 5–20 °dGH (about 89–358 mg/L as CaCO3)
Salinity: Freshwater; some populations tolerate mild brackish conditions, but routine salt is unnecessary
Lighting: Normal lighting with planted and shaded areas
Placement / zone: All levels, especially lower and middle water
Filtration: Use mature biological filtration sized for the complete adult american flagfish group, with guarded intakes and accessible mechanical capture. Keep flow gentle to moderate with well-oxygenated planted areas where the fish lives, and maintain undetectable ammonia and nitrite.
Aeration: Maintain reliable surface agitation and oxygen exchange at all times. Increase aeration during warm weather, medication, transport recovery, heavy feeding or any sign of rapid breathing.
Maintenance: Perform regular matched-water changes guided by nitrate and waste, remove uneaten food and trapped detritus, clean mechanical media without disrupting the biofilter, and record feeding, body condition, respiration and aggression.

Identity and search names

Use only for Jordanella floridae. Do not confuse it with similarly patterned pupfishes or other North American killifishes.

Search names: Flagfish, Florida flagfish, American-flag fish

Environment and housing

Use a mature aquarium with open swimming areas, dense plants, wood and visual barriers. Maintain strong oxygenation without excessive current.

Social structure: Pairs or structured groups can work. Monitor male-to-male aggression, female harassment and fin nipping.

Feeding and nutrition

Feeding ecology: Omnivorous grazer; algae and plant material plus small invertebrates and quality prepared foods

Feeding routine: One or two measured feeds daily unless the feeding plan states otherwise

Breeding, reproduction or spread

Eggs are deposited among plants or spawning material. Males may guard a spawning area, but behaviour varies and adults may eat eggs or fry.

Detailed care and app-ready planning

Identity scope: Use only for Jordanella floridae. Do not confuse it with similarly patterned pupfishes or other North American killifishes.
Adult size and space: Plan around 6.5 cm adults. A pair needs at least 75 L; groups require more floor area, cover and multiple territories.
Social structure: Pairs or structured groups can work. Monitor male-to-male aggression, female harassment and fin nipping.
Swimming zone or placement: Uses all levels but spends much time grazing surfaces in lower and middle water.
Feeding ecology: Omnivorous surface grazer taking algae, plant matter, small crustaceans, insect larvae and other tiny foods.
Feeding plan: Offer plant-rich staple food daily with measured animal-protein feeds. Confirm timid fish receive food.
Water stability: Maintain 18–24 °C, pH 6.0–8.0 and 5–20 °dGH. Avoid overheating and rapid mineral changes.
Habitat structure: Provide dense plants, open grazing surfaces, visual barriers and a secure lid.
Compatibility plan: Avoid delicate long-finned fish, very small shrimp and warm-water species requiring temperatures above this range.
Breeding or reproduction plan: Use dense plants or spawning mops, remove eggs or adults if predation occurs, and prepare tiny fry foods before spawning.
Quarantine: Quarantine in a separate cycled aquarium and monitor appetite, fins, respiration, skin and waste.
Welfare checks: Check body condition, fin damage, chasing, feeding access and signs of overheating or low oxygen.
Biosecurity and release: Never release fish, eggs, fry, plants, aquarium water or sediment into drains, dams or waterways. Verify current Australian import and South Australian possession, sale and movement rules before obtaining stock.
Main risk: Territorial fin damage and keeping a subtropical fish too warm.
Adult projected load: Project biological load from the full adult american flagfish group, adult body mass, feeding pattern, activity and social requirement rather than juvenile sale size. A pair or structured group has a moderate waste load, while grazing, spawning territories and fin-nipping risk add management burden.
Filtration: Use mature biological filtration sized for the complete adult american flagfish group, with guarded intakes and accessible mechanical capture. Keep flow gentle to moderate with well-oxygenated planted areas where the fish lives, and maintain undetectable ammonia and nitrite.
Aeration: Maintain reliable surface agitation and oxygen exchange at all times. Increase aeration during warm weather, medication, transport recovery, heavy feeding or any sign of rapid breathing.
Maintenance: Perform regular matched-water changes guided by nitrate and waste, remove uneaten food and trapped detritus, clean mechanical media without disrupting the biofilter, and record feeding, body condition, respiration and aggression.
Overridable warnings: Non-overridable: do not accept persistent ammonia or nitrite, oxygen distress, starvation, chronic aggression or inadequate adult space. Different equipment, stocking or maintenance methods may be used only when measured water quality and adult welfare remain equivalent or better. Do not keep it permanently hot, rely on algae alone or allow a territorial male to injure tankmates.
Identity: Valid species Jordanella floridae. Search names include flagfish and Florida flagfish.
Environment: Use a mature aquarium with open swimming areas, dense plants, wood and visual barriers. Maintain strong oxygenation without excessive current.
Feeding: Provide algae-based and vegetable-rich prepared food, soft algae growth and small frozen or live invertebrates. Do not rely on algae alone.
Breeding: Eggs are deposited among plants or spawning material. Males may guard a spawning area, but behaviour varies and adults may eat eggs or fry.
Adult size and space: Plan around 6.5 cm adults. A pair needs at least 75 L; groups require more floor area, cover and multiple territories.
Biosecurity and release: Never release fish, eggs, fry, plants, aquarium water or sediment into drains, dams or waterways. Verify current Australian import and South Australian possession, sale and movement rules before obtaining stock.
Welfare Risk: Chronic harassment, unsuitable heat and an animal-protein-heavy diet are the main avoidable failures.

Compatibility, welfare and risk

Compatibility: Best with robust peaceful subtropical fish; may nip fins and become territorial during spawning

Welfare: Chronic harassment, unsuitable heat and an animal-protein-heavy diet are the main avoidable failures.

Main warning: This is a cool-to-warm subtropical fish, not a permanently hot tropical community species. Males can become territorial and may damage slow long-finned tank mates.

Biosecurity and release

Never release fish, eggs, fry, plants, aquarium water or sediment into drains, dams or waterways. Verify current Australian import and South Australian possession, sale and movement rules before obtaining stock.

American flagfish