fish · Cyprinodontidae
Florida flagfish
Jordanella floridae
Wild range: Peninsular Florida, United States — St. Johns and Ochlockonee River drainages south through peninsular Florida. Type locality Lake Monroe, Florida (St. Johns drainage). Does not occur in Mexico. Introduced elsewhere via the aquarium trade (establishment uncertain). (North America)
At a glance: Florida flagfish care
Compiled reference information. Review the care notes and original sources below.
What temperature is listed for Florida flagfish?
The compiled profile lists 18.0–30.0 °C for Florida flagfish (Jordanella floridae). Check the original sources below for context and differing recommendations.
What tank size is listed for Florida flagfish?
The profile lists a minimum tank volume of 20.0 US gallons (76.0 liters). Volume alone does not establish suitability; consider dimensions, group size and other inhabitants alongside the full care notes.
What pH is listed for Florida flagfish?
The compiled profile lists a pH of 6.5–8.5. Review the cited care sources alongside the other water parameters in this profile.
Natural habitat
A stocky North American pupfish/killifish of shallow, heavily vegetated freshwater marshes, backwaters, canals, ditches, and sluggish streams in peninsular Florida; occasionally enters lightly brackish water (Seriously Fish; FishBase; Aquarium Co-Op). Males show red-and-blue flank striping with a yellow shoulder patch that suggested the American flag; both sexes carry a dark mid-body spot and females often a dark blotch on the rear of the dorsal fin. One of the few hobby fish that reliably grazes hair algae and black beard algae, so it is popular in unheated planted tanks and outdoor summer ponds.
Where they are found
Catalog primary locked as Jordanella floridae Goode & Bean, 1879 (ITIS TSN 165694 valid; CoF Current status Valid as Jordanella floridae Goode & Bean 1879, Cyprinodontidae: Cyprinodontinae; original description Goode 1879, Proceedings of the United States National Museum 2(73):117, type locality Lake Monroe, Florida; syntypes USNM). Authorship often styled 'Goode and Bean in Goode, 1879' (ITIS/CoF). Only extant species in Jordanella per FishBase/ITIS. Formerly placed as Cyprinodon floridae (Seriously Fish). AFS/ITIS English names: American flagfish, flagfish. Trade also Florida flagfish / American Flag. Endemic to peninsular Florida south of the Ochlockonee and St. Johns basins (Seriously Fish; FishBase). IUCN Red List Not Evaluated (FishBase Ref. 130435 Version 2025-2). A line-bred 'balloon' strain exists. Parental-care lore conflicts: FishBase/ACO cite male egg-guarding/fanning; Seriously Fish says fractional spawning without pit-digging or extended care — noted in reproduction.
Aquarium care
Hardy cool-tolerant algae grazer for planted unheated or lightly heated tanks. Locked minimum 20 US gallons (~76 L) for a pair (Aquarium Co-Op, Tropical Treasures Wyo, Aquendium, Fish Laboratory); Seriously Fish ~14 US gal / 60×30 cm footprint is only just acceptable for a single pair — larger is better for a 1 male : 2–3 female harem. Locked ~18–30°C, pH ~6.5–8.5, GH ~2–20 dGH (Seriously Fish and Aquarium Co-Op agree on temp and pH; SF hardness 2–20; TTW GH 5–20; Aquendium 5–15). Cooler room temperatures (~18–24°C) suit color and longevity; avoid sustained heat above ~28–30°C. Dense plants, broken sightlines, a tight lid (jumpers), and gentle sponge or modest HOB filtration. Encourage some filamentous algae. Keep more females than males; add space for each extra male.
Feeding
Omnivore with a strong algae/plant component: wild diet includes worms, crustaceans, insects, and plant matter (FishBase; Seriously Fish). In the aquarium they take quality flakes/pellets, vegetable/spirulina foods, blanched zucchini, and regular live or frozen Daphnia, Artemia, and bloodworms (Aquarium Co-Op; Seriously Fish). Slight underfeeding encourages hair-algae and black-beard algae grazing. Food must include vegetable/algal content if the tank lacks algae.
Compatibility
Semi-aggressive and territorial, especially males when breeding — not a gentle community nano fish. Best with similarly sized, fast, short-finned tankmates (zebra danios, corydoras, loaches, hardy livebearers per Aquarium Co-Op). Avoid long-finned or slow fish (bettas, fancy guppies, angels) and dwarf shrimp, which flagfish will eat (Aquarium Co-Op; Aquendium). Species tank or cool-water community with heavy plant cover preferred. Community_safe false.
Breeding
Easiest as a pair or 1 male with 2–3 females in a planted 10–20 gal with java moss or yarn mops and a sponge filter. Warm toward the mid/upper band and condition with live/frozen foods and greens to trigger spring–summer-style spawning (Aquarium Co-Op). Eggs attach to plants/algae; remove eggs or adults to a hatching container of matching water if higher yield is wanted. Hatch in about 7–14 days; first foods vinegar eels/powdered fry food, then Artemia nauplii and microworms (Seriously Fish; Aquarium Co-Op).
Sources
Compiled from multiple independent care sheets — not copied from a single site.