Mary Allen
Because they have lived on earth for hundreds of millions of years and have changed little since then, Tadpole crabs are referred to as “living fossils”.
Characteristics
What do Tadpole Shrimp look like?
The basic structure of the Tadpole Shrimp corresponds to that of the other crayfish species: They have a head, several body sections with pairs of legs, and other sections that have no legs. Altogether there are three groups of Tadpole Shrimp: Fairy Shrimp (Anostraca) look a bit like water fleas. Unlike the other two groups of Tadpole Shrimp, they have no shield or armor covering their bodies.
They are 23 to 28 millimeters tall. They have so-called compound eyes on their heads, which consist of many individual eyes and sit on stalks. They also have feelers, also called antennae. The males also have appendages on these feelers, which they use to clasp the females when mating.
Back shavers (Notostraca), as the name suggests, have a flat backplate covering the head and the portions of the body that bear legs. Their eyes are on the head and not on stalks. They also have antennae and grow up to eleven centimeters in size. The third group of Tadpole Shrimp is the Shell Shellers (Conchostraca).
Shellers are crabs that are half a centimeter to two centimeters in size and look like a shell: they have a two-part shell that protects the body from injuries.
Where do Tadpole Shrimp live?
Tadpole Shrimp are found in freshwater and saline ponds around the world. Some species live worldwide, others are limited to certain regions. Tadpole Shrimp need water to survive. But small ponds are enough for them. If these dry out, the Tadpole Shrimp eggs, which can last for decades, can survive and continue to develop when the ponds are filled with water again. Tadpole Shrimp mainly populate waters where no fish live.
What types of Tadpole Cancer are there?
Today there are three different orders of Tadpole Shrimp: Fairy Shrimp (Anostraca), Back Shellers (Notostraca), and Shell Shellers (Conchostraca).
How old do Tadpole Shrimp get?
The life expectancy of Tadpole Shrimp is short and varies depending on the species: Some only live four weeks, others such as e.g. B. American Triops species are on average up to three months old, European Triops species up to 4 months old. The record is for an animal that reached the age of six months.
Behavior
How do Tadpole Shrimp live?
Tadpole Shrimp are an ancient group of animals. Their ancestors probably originated in the ocean. Researchers estimate that the oldest fossilized remains of these animals are over 500 million years old. There is a very specific reason why they are only found in salt and freshwater ponds today:
When the first predatory fish appeared around 300 million years ago and also ate Tadpole Shrimp and above all their larvae, they migrated to a safer habitat. Fairy shrimp have a quirk: they always swim belly up. They have bristles on their legs that they use to filter food from the water.
Fairy shrimp have lived on Earth for about 100 million years. The oldest living animal species in the world belongs to the dorsal shells: the Tadpole Shrimp species “Triops” has lived on earth for 220 million years and has not changed since then. Back shellers live mainly on the bottom of water bodies. They move belly down.
They only swim belly up on the surface of the water when they run out of oxygen. The mussel shellers usually lie sideways on the bottom of the water or even dig themselves into the silt so that only their rear end protrudes. If they do swim, they do so with their backs up. Relatives of them who are now extinct lived on Earth 400 million years ago.
Friends and foes of Tadpole Shrimp
Many animals live in and around the water and feed on predatory prey on Tadpole Shrimp. These include mainly fish, but also birds, amphibians, and some aquatic insects.
However, the Tadpole Shrimp do not need to worry about the safety of their offspring: their permanent eggs can survive being in the stomach and intestines of enemies without damage, are excreted again, and continue to develop again if they land in a pond or puddle.
How do Tadpole Shrimp reproduce?
The female fairy shrimp have a brood sac on their abdomen. In it, the mature eggs are moved back and forth with the help of special muscles so that they are sufficiently supplied with oxygen. After fertilization, the eggs develop in the water. However, they can also survive times when a pond dries up.
If the water then rises again, they continue to develop, and larvae hatch that is just a quarter of a millimeter in size. They molt several times until they finally grow into an adult animals.
All dorsal moths that live in our waters are females. They reproduce by virgin generation (parthenogenesis), i. H. their eggs do not need to be fertilized to develop. The eggs mature in brood pouches attached to the 11th pair of legs.
In contrast, in other regions such as southern or western Europe and North Africa, there are both males and females among the backswimmers. They mate to reproduce.
Mussel shells can reproduce in many ways: their eggs can develop without fertilization (parthenogenesis, or virgin birth), they can fertilize themselves or they mate normally, and the eggs are fertilized by males.
Just two to three weeks after hatching, the Tadpole Shrimp are mature and can reproduce.
Care
What do Tadpole Shrimp eat?
Fairy shrimp feed primarily on plankton, i.e. plant and animal microorganisms that live in water. Back shellers are omnivores. They feed on plankton and mosquito larvae. But they also like to eat worms or tadpoles. And they don’t even stop at the fairy shrimp that are related to them. They rummage through the mud with the leading edge of their shell. The food is then carried forward in the abdominal groove to the mouth.
Keeping Tadpole Shrimp
You can breed Tadpole Shrimp yourself. For this you need an aquarium that is free of cleaning agent residues; it must therefore be rinsed out thoroughly with clear water. It is best to place the tank in a bright but not sunny place and use a timer to switch the lighting on so that it burns 12 hours a day.
Either a layer of pure sand or some soil is filled in as substrate. You can buy packets of Tadpole Shrimp Eggs at pet stores. You fill it in the basin, add two to three centimeters of distilled water and then fill it up with tap water. The water should be around 22-24°C warm. Finally, the small larvae hatch and develop into Tadpole Shrimp.
Care plan
The Tadpole Shrimp do not need any food for the first three to four days because the breeding mix already contains enough nutrients. Only when they are about half a centimeter in size do you put special food in the water. If the water gets dirty, you should never change it all at once. This would be a shock for the animals, which hardly survive. Similar to an aquarium with fish, about a third of the water is sucked off with the help of a hose, and new water is carefully refilled.