mummichog
Fundulus heteroclitus · Fundulidae · omnivore
A small fish of marshes and tidal creeks on the east coast of North America, also recorded as native to Mexico. It is not a target of sport fishing.
Also called: fúndulo-das-marismas, fúndulo, mummichog
- maximum
- 15 cm
the right time
to be on the water
Choose the place and the species. The index, from 0 to 100, combines weather, sun, moon and tide with each fish's habits. Up to 28 days, with each day's confidence.
Reading the weather across 3 global models and 31 simulations…
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hour by hour
tap or drag on the chart to read each hour · on a keyboard, arrow keyssee hour-by-hour table
why this index at —?
choose the day
Each card shows the day's index (0 to 100) and, below it, a strip with the index for each hour, from 0h to 23h. from poor to excellent.
the fishing month at a glance
what's the best window for the crew?
Choose how many fishing days. We compare each stretch by its average index, discount days with a warning or closed season, and show the 3 best.
trend for the coming weeks
Line: the middle value of 31 simulations of the American GEFS model. Band: where 8 out of 10 fall. Narrow, firm trend; wide, high uncertainty.
everything about the mummichog
who is the mummichog
A fish of the family Fundulidae, found in shallow brackish waters. It reaches 15 cm and lives in salt marshes and tidal creeks, in the intertidal zone, sometimes in nearby freshwater stretches. It is a resident fish: it stays in the same area and always returns to the same spot. It spawns in the shells of a mussel, Modiolus demissus. It is sold for aquariums and caught for sale, but it is not a target of sport fishing.
Essential profile. Identification, where it occurs and rules, with data from FishBase and the cited regulations. Season, time of day, technique and bait are added once we have a good source for the mummichog; in the meantime, see the similar species.
fun facts
- It breathes air when it leaves the water and always returns to the same area.
- It was introduced to southern Portugal and Spain, where it threatens native species.
identification
Upper profile more convex, and sides with dark bars alternating with silver stripes. Males have a small ocellus, a round spot with a ring, at the rear of the dorsal fin. It looks almost identical to Fundulus grandis, but this species has a more convex upper profile, dark bars alternating with silver, and the male's ocellus.
where found
It lives on the North American Atlantic coast, from the Gulf of St. Lawrence in Canada to northeastern Florida. In Latin America it is recorded as native to Mexico.
Habitat: Salt marshes, tidal creeks and nearby freshwater stretches, in the intertidal zone.
rules for the mummichog
Summary of the regulations we found, with the source for each. Rules change; before keeping or transporting fish, check with the state environmental agency.
We found no species-specific rule beyond the region's general rules.
catch and release
catch and release Releasing the fish alive, quickly and with a wet hand. During a closed season it isn't always allowed: what the regulation says applies.
It has no spines or venom and poses no danger to people.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.00933, b = 3.17; FishBase (relação peso-comprimento bayesiana, estimativa da própria espécie)). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
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sources and references
Essential profile: size, length-weight, depth, countries and conservation come from FishBase and the cited regulations, and the texts were written from those sources. Season, time of day, sensitivities, technique and baits and lures are not included yet, because we did not find a good source for this species.
- scientific FishBase: Fundulus heteroclitus (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Fundulus heteroclitusNames by country and language.
similar species
where each number comes from
The weather comes from three independent global models, cross-checked hour by hour: when they agree, confidence goes up; when they diverge, the band between them shows on the chart. Beyond 16 days, we use the GEFS ensemble of 31 simulations: if 20 of the 31 predict rain, the chance of rain is 65%. Sun and moon are calculated astronomically, with no uncertainty.
The index adds up, weighted for each species: time of day (species curve anchored to real sunrise and sunset), moon (transits, rise and set, phase), pressure (3 h trend and 24 h swing), water temperature (in rivers, estimated from air temperature; at sea, estimated by an ocean model), wind, rain, clouds, tide and the month in the species' cycle.
sources for this lookup
how accurate the forecast is
Accuracy measured in the reference project (4 regions, 93 days, forecast vs. observed): maximum temperature is off by 0.6 °C on average the next day and 1.7 °C at 7 days; rain of 5 mm or more is detected 76% of the time the next day and 57% at 7 days. Detection isn't everything: the false alarm rate isn't published here yet, and 93 days in 4 regions is still a small sample. We now also measure every day, at the app's destinations: