threebanded butterflyfish
Chaetodon humeralis · Chaetodontidae · omnivore
Butterflyfish of shallow eastern Pacific reefs, with a yellowish-cream base color cut by dark vertical bands. It has commercial use, mainly for aquariums.
Also called: borboleta-de-três-faixas, mariposa de tres bandas, threebanded butterflyfish
- maximum
- 25 cm
- depth
- 3–12 m
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
slide your finger or mouse over the chart to see each hoursee 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 threebanded butterflyfish
who is the threebanded butterflyfish
Butterflyfish of the family Chaetodontidae, with a tall, disk-shaped, strongly compressed body, a steeply sloped head profile and a pronounced snout. It reaches 25 cm, and the common size is 12 cm. It lives on shallow reefs and rocky shores of the eastern Pacific, from southern California to Peru, including the Galápagos and Central America, from 3 to 50 m, most often 3 to 12 m. It is usually seen in pairs or small groups near rocks, where it feeds on algae and bottom invertebrates. It forms pairs during breeding. Its commercial value is mainly for aquariums.
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 threebanded butterflyfish; in the meantime, see the similar species.
fun facts
- Forms schools together with the Pacific spadefish (Chaetodipterus zonatus).
identification
Tall, disk-shaped, strongly compressed body, yellowish-cream with five or six dark vertical bands on the head, body and tail. The head profile is steeply sloped and the snout is pronounced. The vertical bands are the feature that most helps identify it. On the same reefs, the blacksnout butterflyfish (Johnrandallia nigrirostris) has a dark-smudged snout and a black-outlined eye.
where found
From Mexico to Colombia, Ecuador and Peru, passing through Central America, on shallow reefs of the eastern Pacific.
Habitat: Shallow reefs and rocky shores, from 3 to 50 m, most often 3 to 12 m.
rules for the threebanded butterflyfish
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.
No danger to anglers has been recorded. It is a small, delicate fish: handle it with a wet hand and return it to the water.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.02399, b = 3.04; 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: Chaetodon humeralis (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Chaetodon humeralisNames 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: