Hardhead is a large freshwater fish from the carp family. It lives in California rivers, has a large sturdy head, and can grow almost up to one meter.
Hardhead differs from other cyprinid fish by its very strong head and large body size. It is important for nature because it participates in the food chains of California's rivers and helps control the population of aquatic insects.
Immature form that undergoes metamorphosis before adulthood.
Worker
birth time
bottom
Dogs, dolphins, lynx hang out for 9-25 years and party on their birthday three times a year
m
Map
will celebrate their {n} birthday
shallow coastal zones of rivers and lakes
g
t
When your next jubilee falls in {name} life years
Human
detritus, eat dead remains of plants, animals and all kinds of organic debris on the bottom
days
Warm summer
How old you would be if you lived as {name}
Theoretical maximum lifespan estimated from the Dynamic Energy Budget (DEB) mathematical model. This value reflects a biological potential derived from metabolic parameters, not from direct observation — real recorded lifespans are often significantly shorter.
adult
Maturity
organic debris
fish of small size
Melon
About health
cool, lots of coniferous trees, snow in winter
When your next birthday would fall if you lived as {name}
Repro interval
results
summer warm and almost no rain
summer warm, winter not very cold
Colors
Sex
Upcoming jubilees
Gremllins
mo
Trophic type
Filters
small fish
Upcoming birthdays
standing fresh waters — lakes, ponds, oxbow lakes
Truly long lives: 40-100 years. Bowhead whales, albatrosses, giant tortoises recall their birthday at most once a year
Lifespan
Height
Desert and dry shrubs
insect larvae and caterpillars
Age (from birth to death)
Foraging occurs on the floor of aquatic or terrestrial habitats.
Wanderers
algae
Jubilee = every 10th birthday
Earliest developmental stage inside an egg or womb.
Business sausages
Scales count
Lifespan average
What do they look like?
Maturity
emergence (insects)
end of lifespan
How do they live?
fertilization / egg laying
How do they behave?
birth / hatching
metamorphosis / end of larval stage
end of acceleration
Share
swampy freshwater biotopes — peat bogs, marshes, river mangroves
Find a pet...
Mature, fully developed individual capable of reproduction.
Freshwater
Pets
all rivers and lakes
Primary oral structure used to seize, manipulate, or ingest food.
Nearctic realm
{name} jubilee
cm
Temperate coniferous forest
Old-timers
Find an animal or breed...
mouth
turns
Rascals
Dorsal fin count
Litter size
Map data sources: Ecosystem classification — IUCN Global Ecosystem Typology (Keith et al., 2022), indicative distribution maps Keith et al. (2020), https://doi.org/10.5281/zenodo.3546513; Large Marine Ecosystems — NOAA LME Program; Bathymetry — GEBCO Bathymetric Compilation Group (2026), GEBCO_2026 Grid, https://doi.org/10.5285/4f68d5c7-45eb-f999-e063-7086abc036fa; Climate data — Generated using Copernicus Climate Change Service information; Species occurrence data — GBIF.org, Derived dataset "all animals", https://zveriki.com/dataset/dataset.tsv; Terrestrial ecoregions — RESOLVE Ecoregions 2017 (Dinerstein et al., 2017), CC BY 4.0
How to care for them?
Living from 25 to 40 years. Orangutans, bald eagles, African elephants celebrate their birthday twice a year
°C
Not specified
Actively searching habitats to locate food items.
Egg color
Where are they found?
Species lacks any fixed or lasting shelter structure.
from 0.8 to 1.2 kilograms, 0.6 – 1.2 meters
all rivers and lakes
Locomotion through water employed while searching for or capturing prey.
Legendary longevity: over 100 years. Galapagos tortoises, Greenland sharks, ocean quahogs celebrate with family once every 4 years
Offspring
Elders
Bro
lakes and ponds
freshwater marsh and wetlands
Taxons
if born as {name}
omnivore
age
birth date
Head size
swimming
no permanent shelter
freshwater coastal and creek
Close
water column
was
Career from 7 to 15 months. Dwarf hamsters, voles, field crickets celebrate their birthday twice a month
The basics
My weight?
Non-stop carnival: they only live a few days. Mayflies, rotifers, midges celebrate their birthday more than twice a day
primary food sources
Potential Habitat
d
In husbandry
Feeds while suspended in open water between surface and bottom.
On the go from 1.3 to 3.5 years. Forest mice, anoles, rainbow fish party on their birthday once a month
Feeding occurs in water bodies such as rivers, lakes, or oceans.
Mass
Mosquitoes, fruit flies, small crustaceans hustle for up to 7 months and throw a birthday party every week
Body size
aquatic
{name} birthday
Nearctic realm
No results found
North America and Greenland, from tundra to forests
Caudal fin count
On the map
all life stages
Female ♀
Map data sources: Ecosystem classification — IUCN Global Ecosystem Typology (Keith et al., 2022), indicative distribution maps Keith et al. (2020), https://doi.org/10.5281/zenodo.3546513; Large Marine Ecosystems — NOAA LME Program; Bathymetry — GEBCO Bathymetric Compilation Group (2026), GEBCO_2026 Grid, https://doi.org/10.5285/4f68d5c7-45eb-f999-e063-7086abc036fa; Climate data — Generated using Copernicus Climate Change Service information; Species occurrence data — GBIF.org, Derived dataset "all animals", https://zveriki.com/dataset/dataset.tsv; Terrestrial ecoregions — RESOLVE Ecoregions 2017 (Dinerstein et al., 2017), CC BY 4.0
Potential habitat modelled from GBIF occurrence data. Map © Zveriki.com, licensed under CC BY 4.0.
birth year
lots of grass, few trees, rains occur
Maturity
sq mm
yr
How similar?
Egg size
Male ♂
until the celebration
age as {name}
How do they breed?
On the go from 3.5 to 6 years. Hedgehogs, crows, lizards treat themselves to birthday snacks 6 times a year
What if eaten?
Neither
from birth to adulthood
What do they eat?
insect larvae
Where do they live?
Immature individual that has not yet reached reproductive maturity.
early young
Freshwater
Duration
This is me
Warm summer with almost no rain
stream
freshwater
Gamers
aquatic plants and algae
How are they built?
Temperate steppe
mm
Theoretical lifespan
ml
Stars
Link copied
My age?
wk
My size?
Asexual
swap
freshwater environment — rivers, lakes, ponds, swamps
Rabbits, falcons, red-eared turtles hang out for 6-9 years and party on their birthday four times a year
Where do they take shelter?
Head color
celebrated their {n} birthday
When you would have been born if you lived as {name}
Daddies
Lifespan maximum
foraging
river
Hermaphrodite ⚥
North America and Greenland, from tundra to forests
embryo
Length
kg
very hot and dry, rare rains, cacti live
Observations
◉{N} more on tap