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Aggressive predator that eats anything it can swallow.
This one is best kept on its own, or with its own kind.
Aggressive predator that eats anything it can swallow. Kept alone or with large tolerant fish.
Check your local laws. USFWS rates it High risk for the contiguous US. Named in state rules of Arizona, California, Hawaii, Mississippi, Nevada, Oklahoma, Texas and Utah (restrictions vary; check the state agency). Florida is not named in the USFWS list, although the fish is invasive there. Check the rules where you live before you buy one, and never release it into the wild.
Live feeder fish, guppies, shrimp and fish strips; wean to frozen if possible.
Tap a food to see what it is.
Females are clearly larger (about 10-15 cm) than males (about 8-10 cm); males have a gonopodium (modified anal fin).
Common problems. Tap one to see the signs. This is a guide, not a diagnosis.
Livebearer · Moderate
Livebearer with internal fertilisation; females store sperm and give birth roughly every 6 weeks (38-49 days in the lab). Newborns are about 15-16 mm and piscivorous from birth; fry and young are cannibalistic, so they need separating and live food.
A single pair in a large tank; separate the female before birth.
Large tank with dense floating plants and cover; fry need a separate nursery.
Warm 26-28 C water and live feeder fish.
Around 100 young per brood on average (up to 322 recorded), about every 6 weeks.
Feed baby brine shrimp then tiny feeder fish; cannibalism is intense.
A specialist fish-eater from the Atlantic slope of Mexico and Central America with long, toothy pike-like jaws, the largest member of the livebearer family. Released from a medical research programme in 1957, it is now established in south Florida, where it hunts small fish near the surface.
Austrian zoologist Rudolf Kner described this predatory livebearer in 1860. Its long jaws and pike-like shape make it an unusual member of the guppy family.
First described by Rudolf Kner in 1860. Named for Named after Belize.
15 facts checked with sources
Valid name (Catalog of Fishes, via USFWS). The subspecies B. b. belizanus and B. b. maxillosus (Hubbs 1936) are no longer considered distinct (PFK). Also sold as pike killifish or pike topminnow.
FishBase: Belonesox belizanus summary · USFWS Ecological Risk Screening Summary: Pike Killifish (Belonesox belizanus), web version 2 Jul 2025Legacy has no family field; sourced value recorded.
FishBase: Belonesox belizanus summarysize-pick: No Seriously Fish profile exists. Aquarium figure (PFK) and the Florida Museum both give 15 cm TL for large females; FishBase lists a single 20 cm TL maximum (Lucinda 2003, oddly labelled male/unsexed although females are the larger sex). The 20 cm record is kept in the note only. All figures are TL. Legacy 20 cm is the record figure, not a typical adult.
Practical Fishkeeping (Matt Clarke, Sept 2004): Belonesox belizanus, the Pike topminnow · Florida Museum of Natural History: Pike Killifish (R. H. Robins) · FishBase: Belonesox belizanus summaryNo Seriously Fish profile. PFK recommends about 25 °C and stresses wide tolerance; FishBase (wild range) 25-37 °C. USFWS ERSS notes a lower lethal temperature of about 10 °C. Legacy 24-30 is consistent with these.
Practical Fishkeeping (Matt Clarke, Sept 2004): Belonesox belizanus, the Pike topminnow · FishBase: Belonesox belizanus summaryPFK (husbandry) 7.5-8.0; FishBase 6.0-8.0. Legacy 7-8.5 runs above both upper limits. Euryhaline: tolerates brackish and even sea water (salinity to 40 ppt, FishBase).
Practical Fishkeeping (Matt Clarke, Sept 2004): Belonesox belizanus, the Pike topminnow · FishBase: Belonesox belizanus summaryLegacy has no hardness; FishBase range recorded. PFK says it can live in soft to hard water.
FishBase: Belonesox belizanus summaryPFK gives only tank length (90-120 cm). Assuming 35 cm depth and 35 cm height for the 90 cm minimum: 90 x 35 x 35 = 110,250 cm³ = ~110 L. Legacy 300 L is well above this source; the fish is a surface ambusher so a long tank matters more than volume.
Practical Fishkeeping (Matt Clarke, Sept 2004): Belonesox belizanus, the Pike topminnowLegacy 'a' = aggressive (predatory).
Practical Fishkeeping (Matt Clarke, Sept 2004): Belonesox belizanus, the Pike topminnow · Florida Museum of Natural History: Pike Killifish (R. H. Robins)Legacy 't' = top.
Florida Museum of Natural History: Pike Killifish (R. H. Robins)Legacy has no range field. IUCN: Least Concern (assessed 28 March 2018, per FishBase).
Florida Museum of Natural History: Pike Killifish (R. H. Robins) · FishBase: Belonesox belizanus summaryLegacy idea is right (females bigger, males with modified anal fin) but its sizes (male 12 cm, female 20 cm) are too large.
Practical Fishkeeping (Matt Clarke, Sept 2004): Belonesox belizanus, the Pike topminnow · Florida Museum of Natural History: Pike Killifish (R. H. Robins)Legacy says the mother eats the fry; sources stress cannibalism by fry and young fish generally. Legacy brood size is too low (see breeding.eggs).
Florida Museum of Natural History: Pike Killifish (R. H. Robins) · Practical Fishkeeping (Matt Clarke, Sept 2004): Belonesox belizanus, the Pike topminnow · USFWS Ecological Risk Screening Summary: Pike Killifish (Belonesox belizanus), web version 2 Jul 2025Legacy 20-80 fry per brood every 6 weeks: interval is right, brood size is too low.
USFWS Ecological Risk Screening Summary: Pike Killifish (Belonesox belizanus), web version 2 Jul 2025 · Florida Museum of Natural History: Pike Killifish (R. H. Robins) · Practical Fishkeeping (Matt Clarke, Sept 2004): Belonesox belizanus, the Pike topminnowLegacy text is right in substance. 'Central America' should include Mexico. ERSS adds that the Florida fish can switch to eating shrimp.
USFWS Ecological Risk Screening Summary: Pike Killifish (Belonesox belizanus), web version 2 Jul 2025 · Florida Museum of Natural History: Pike Killifish (R. H. Robins)USFWS says its list may not be comprehensive and excludes blanket rules that do not name the species. No source checked states a Florida ban; Florida FWC rules were not checked directly. Not CITES-listed (FishBase: Not Evaluated). Legacy "restricted or banned in some US states" is right but vague.
USFWS Ecological Risk Screening Summary: Pike Killifish (Belonesox belizanus), web version 2 Jul 2025