At a glance the quick version
Looks how to spot one
Short, stocky scaled fish
A sturdy little killifish with a blunt, bulldog-like snout. Adult males carry longer dorsal and anal fins than females, while females are rounder and show a dark spot towards the back of the dorsal fin.13
Personality what they are like
An active, fairly robust fish. Males claim small territories, but several can share a roomy tank. Often happiest in a species tank, though it can join a spacious community.1
Daily activity how busy a day looks
Moves around plants and open water through the day; give it room so males can each hold a patch.1
Grooming and care the hands-on bits
Temperature around 18-30 C, pH 6.5-8.5, hardness 2-20 dGH. Unheated tanks at room temperature are often fine within this range.12
Home where they are happiest
At least a 60 x 30 cm footprint (about 54 litres), more for groups. Plenty of plants and a gentle flow, copying the shallow weedy marshes and ditches it comes from.13
Food basics what goes in the bowl
Omnivore. Eats small invertebrates and also plant matter and algae. Offer quality dried food plus live or frozen daphnia and brine shrimp, and some vegetable-based food if algae is scarce.123
Company who they like around
Can be kept singly or in small groups; give males space and visual barriers.1
The story where it all began
Goode and Bean described the species in 1879 from Lake Monroe, Florida. The genus honours ichthyologist David Starr Jordan, and the fish has been a long-standing favourite in the aquarium hobby.31
Fun facts for the dinner table
- 1
It earns its name from the dominant male's pattern, which looks a bit like the US flag with a dark 'stars' patch and red stripes.3
- 2
It is noted for laying very few eggs, around 20 over several days.2
- 3
Aquarists value it as one of the few fish that will eat hair algae.3
- 4
Sources differ on parenting: FishBase describes males guarding and fanning eggs, while Seriously Fish reports no lasting parental care.1
Recognised by the official bits
- FishBase
- Listed as Not Evaluated by the IUCN.2
- Guinness World Records (via FishBase and Wikipedia)
- Cited for laying the fewest eggs of any fish, about 20 spread over several days.2
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a American Flagfish. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- FeedingSmall amounts once or twice a dayevery day
- Temperature checkevery day
- Water changeAbout 25% of the waterevery week
- Water testevery week
- Glass cleanevery week
- Filter rinseRinse in old tank water, never tap waterevery month
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at support@furrydiary.app and we will fix it.
- Seriously Fish: Jordanella floridae seriouslyfish.comused for size, range, care parameters, behaviour, diet
- FishBase: Jordanella floridae fishbase.seused for size, range, egg count, IUCN
- Wikipedia: Flagfish en.wikipedia.orgused for description, colours, history, fun facts
Checked 2026-09-30. Text is written in our own words from these sources.