Fairy shrimp are larger crustaceans that move slowly. They live in vernal pools, which are small, shallow ponds in forests that get their water from melting snow, rain, or groundwater but dry up at certain times of the year.
Depends on how long the vernal pool remains wet; generally, half a month to six months
Fairy shrimp are between 0. 10 pairs of leg-like appendages called phyllopods that they use for swimming. They are between 5 and 2 inches long. They swim slowly and belly-side up. Their diet affects their color—they are most often orange, but may also be white, blue or green. Females have smaller heads than the males.
Fairy shrimp are filter-feeders that scrape food off the bottom of their vernal pools. They eat algae, flatworm eggs and Arcella—a type of amoeba that have holes through their centers.
Predatory fish do not live in vernal pools, which make them a safe habitat for fairy shrimp. Birds, frogs, salamanders and insect larvae eat species of fairy shrimp.
Fairy shrimp are a fascinating group of small crustaceans that live in temporary pools and lakes around the world Though tiny, these creatures play an important role in aquatic ecosystems. Read on to learn more about what fairy shrimp are, what they look like, where they live, and why they matter
Fairy shrimp belong to the crustacean order Anostraca. There are around 300 identified species spread across 8 families. Most fairy shrimp grow to be 0.24-0.98 inches (6-25 mm) long, though some species can reach up to 6.7 inches (170 mm).
These tiny creatures are called “fairy shrimp” due to their elegant, translucent bodies and the way they seem to “fly” through the water on their delicate legs. They swim upside down and use their many legs, known as phyllopodia to filter food from the water.
Though small, fairy shrimp fill an important niche in the ecosystems where they live. They are a key food source for fish, birds, and other wildlife that rely on temporary waters.
Appearance and Anatomy
Fairy shrimp have long, segmented bodies divided into three sections: head, thorax, and abdomen.
The head contains stalked compound eyes, two pairs of antennae, and mouthparts. One pair of antennae helps fairy shrimp sense their environment, while the other pair is used by males to grasp females during mating.
The thorax makes up most of a fairy shrimp’s body length. It is divided into 11-21 segments, each with a pair of phyllopodia – flattened, leaf-like legs that allow the shrimp to swim and filter food from the water.
The abdomen is the rear section of the body. It does not have appendages except for the telson, which bears tail-like structures called cercopods.
Fairy shrimp have a simple internal anatomy. A tubular heart pumps blood through the body. The nervous system consists of two nerve cords running along the length of the body. They respire through the thin body surface and phyllopodia.
Habitat and Behavior
Fairy shrimp thrive in temporary pools and lakes of varying salinity and alkalinity around the world. They live on all continents and have adapted to habitats from Antarctica to deserts.
These habitats allow fairy shrimp to avoid predation from fish that cannot survive changing water levels or extremes of temperature and salinity. Their durable eggs can survive drying out completely before hatching when the pools refill.
Fairy shrimp swim elegantly through the water column using metachronal movements of their phyllopodia. They filter small organic particles from the water or scrape algae and microbes from surfaces.
An important aspect of fairy shrimp life history is their ability to enter diapause, a dormant egg stage that allows populations to survive unfavorable conditions and disperse to new habitats.
Ecological Role
Though small, fairy shrimp play an outsized role in the temporary waters where they live. Their periodic hatching provides a pulse of food for migrating waterfowl and other species.
For example, in the prairie pothole region of North America, fairy shrimp provide an abundant food source for female ducks and other waterfowl before breeding season. Their hatching coincides with the spring thaw.
Fairy shrimp also support flamingo populations in saline lakes in places like the Middle East and Africa. Their orange-pink color comes from the fairy shrimp they feed on.
Furthermore, fairy shrimp contribute to the biodiversity of ephemeral waters and pass on nutrients through the food chain. Their resting eggs can survive for centuries, allowing them to repopulate temporary pools long after they dry up.
Uses for Humans
The eggs and adults of some fairy shrimp species are harvested by humans for use as fish food in aquaculture and aquariums.
Brine shrimp of the genus Artemia are the most economically important. Their eggs are collected from places like the Great Salt Lake in Utah and hatched on demand to feed developing fish and shellfish on fish farms.
Evolutionary History
Fairy shrimp likely diverged from other branchiopods during the Ordovician Period over 400 million years ago. They adapted to live in freshwater habitats away from marine predators.
The oldest recognized fairy shrimp fossil is Haltinnaias from 365 million years ago. Fairy shrimp then radiated and spread across the ancient supercontinent Pangaea before it broke apart.
Today, fairy shrimp display a “relic” distribution pattern, with related genera often isolated on landmasses that once bordered Pangaea. This suggests they successfully colonized and held much of their potential range early on.
Though often overlooked due to their small size, fairy shrimp are a unique and ecologically vital group of crustaceans. They have adapted to thrive in some of the most extreme and transient aquatic habitats on Earth. Take a closer look next time you come across a temporary pool – you might just see these tiny shrimp fluttering through the water!
Reproduction and Life Cycle
Fairy shrimp generally mate between April and May. Males die shortly after mating, while the females live until the pool dries up. The eggs are released into the water and remain dormant throughout the dry season. Once the pool fills with water again—often October or November—the eggs hatch. As they grow, the larvae go through different molts and gain body segments. By the time they are adults, they have 20 segments.
- E. vernalis is a species of fairy shrimp that is sometimes called the eastern, springtime, or vernal fairy shrimp.
- Fairy shrimp are related to brine shrimp, which are often sold as Sea Monkeys.
- Wildlife or the wind can move dormant eggs in dry vernal pools, but once they hatch, fairy shrimp stay in the same pool their whole lives.
What are Fairy Shrimp?
What is a fairy shrimp?
Fairy Shrimp are fascinating creatures due to their unique characteristics. They are translucent and exhibit different colors based on factors such as age, diet, and bacterial content of the water. Unlike other shrimp species, these crustaceans do not have a hard outer shell.
Are there different types of fairy shrimp?
There are different species of fairy shrimp, including the conservancy fairy shrimp and the vernal pool fairy shrimp, with diverse features that set them apart.
What makes eastern fairy shrimp unique?
What makes the eastern fairy shrimp unique is that it requires forest cover in addition to deep vernal pools. The forest helps shade the pools, allowing them to retain water longer into the growing season, while preventing the pools from exceeding the critical temperature of 68 F that would kill the shrimp.
Do fairy shrimp eat fish?
They are closely related to other small aquatic creatures such as water fleas and brine shrimp. Fairy shrimp can be found in temporary, fish-free water bodies like vernal pools. They thrive in these environments because they can avoid becoming fish food and escape predation from migrating birds which peak later in the season.