bluespotted surgeonfish
Ctenochaetus marginatus · Acanthuridae · omnivore
Small surgeonfish of shallow reefs, with bright blue spots on the head and body. It is almost never caught on rod and is more valuable for the aquarium than for the hook.
Also called: cirurgião-de-pintas-azuis, navajón estriado, bluespotted surgeonfish
- maximum
- 27 cm
- record/max.
- 0.4 kg
- depth
- 9–12 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 bluespotted surgeonfish
who is the bluespotted surgeonfish
Small fish of the surgeonfish family (Acanthuridae), reaching 27 cm, with a short, tall, disk-shaped body. It lives on shallow reefs facing the open sea and in surf zones, in small schools, mainly between 9 and 12 m. It occurs in islands of the central and western Pacific and, in the eastern Pacific, at Clipperton Island, Cocos Island (Costa Rica) and Gorgona (Colombia), with a record also in Panama. It feeds on a film of algae that grows on the rocks. Like all surgeonfish, it has a movable spine on the tail stalk. In fishing it is reef bycatch, and it is valued mainly for the aquarium.
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 bluespotted surgeonfish.
identification
Short, tall body, with bright blue spots covering the head, body and pectoral fins, and longitudinal blue stripes on the dorsal, anal and caudal fins. The blue spots are the main mark for recognizing it among the surgeonfish of the region. Like all surgeonfish, it has a movable spine on each side of the tail stalk, and it is small, up to 27 cm.
where found
Species of the central and western Pacific that reaches the Americas at the Cocos Islands (Costa Rica), Gorgona (Colombia) and Clipperton, with a record also in Panama, on shallow reefs.
Habitat: Shallow reefs facing the open sea and surf zones, generally from 9 to 12 m.
rules for the bluespotted surgeonfish
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.
Not venomous. Like all surgeonfish, it has a movable spine on the tail stalk that can cut; handle it with care.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.02089, b = 2.95; 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: Ctenochaetus marginatus (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Ctenochaetus marginatusNames by country and language.
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: