blue chromis
Azurina cyanea · Pomacentridae · forage fish
Small blue damselfish that swims in aggregations over outer reefs and eats plankton. It is not a target on the line, but it has commercial use and goes into the aquarium trade.
Also called: donzela-azul, azulejo, cromis azul, blue chromis
- maximum
- 15 cm
- depth
- 10–20 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…
—
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 blue chromis
who is the blue chromis
The blue damselfish is a fish of the family Pomacentridae, with a bright blue body, reaching 15 cm. It lives over deep outer reefs, from 3 to 60 m, and usually stays between 10 and 20 m. It forms aggregations to feed on small plankton organisms, mainly copepods. During breeding, the pair bonds, and the male guards and aerates the eggs. It has commercial use and goes into the aquarium trade, but being small it is of no interest to rod 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 blue chromis; in the meantime, see the similar species.
fun facts
- Forms aggregations to feed on plankton.
- When frightened, it hides in the crevices of the corals.
identification
The body is bright blue, almost the same tone on the belly, which is only a little paler, and it has a black line. There are black edges on the spiny dorsal fin, on the upper and lower lobes of the tail and at the front of the anal fin. It lacks the black spot at the base of the pectoral fin that the sun damselfish has, and it is much bluer than that species, which is olive-brown on top. It moves in aggregations over deep outer reefs.
where found
It lives in the western Atlantic, from Bermuda and southern Florida to the Caribbean, with records from the Bahamas and the Antilles. In Latin America it occurs in Mexico, Belize, Cuba, Haiti, Jamaica, the Dominican Republic, Puerto Rico, Trinidad and Tobago and Venezuela.
Habitat: Outer reefs, 3 to 60 m, usually 10 to 20 m.
rules for the blue chromis
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 is harmless to handle. Being small and of no interest to rod fishing, release whatever comes up by chance.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.0123, b = 3.03; FishBase (relação peso-comprimento bayesiana, estimativa)). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
—
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: Azurina cyanea (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Azurina cyaneaNames 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: