What are Triops?

The Earth was inhabited by dinosaurs about 220 million years ago, which dominated the ecosystems of our planet. However, the age of the dinosaurs came to a sudden end and they died in a mass extinction in the Cretaceous-Palaeogene boundary. The asteroid impact ended the existence of many living things on Earth, but some species survived the dinosaurs, among these were the Triops. The Triops survived the mass extinction and have survived to the present day. Triops are the oldest known living animal species on our planet. But what are Triops and where do they come from? The name Triops means „the three-eyed one“ in Greek and is one of the living fossils. Triops is a genus that belongs to the class of gilled crabs (Branchiopoda). This class in turn belongs to the order of dorsal shellfish (Notostraca; called „shield crabs“ or „jawed crustaceans“). Triops belong to the Triopsidae, together with the genus Lepidurus. These are the only family within the dorsal shells. The species Triops cancriformis is considered the oldest known Triops species. This species was recorded as a subspecies Triops cancriformis minor (†) in the 220 million year old Franconian Keuper. Since Triops swam in pools where dinosaurs trudged more than 220 million years ago, it can be said that these are the dinosaurs of the present.

What are Triops?: Way of life

The natural habitat of Triops is puddles and water pools. These temporary bodies of water are formed by seasonal rain showers and flooding and are usually found on clayey soil in the floodplains of rivers. Unfortunately, many occurrences in Europe today are being destroyed by development. There are currently only about 630 known sites in Germany and Austria. This is an alarmingly low number of habitats. Triops living in freshwater hatch from cysts (permanent eggs) mainly between 24 and 72 hours after heavy rainfall. With ideal abiotic factors, the Triops also hatch within ten hours. As a breeder, you can create an optimal environment for hatching in the tank with the right technology, such as an LED lamp. Triops usually stay at the bottom of the water and look for food there or bury the eggs in the sand. You should always provide enough sand in the aquarium, as Triops are passionate diggers.

After 48 hours have passed since hatching, the Triops are fed for the first time. Powdered food should be used for the first few days. After they have grown to a size of about 1 cm, you can move them to a larger tank. After about two weeks, the Triops are fed solid food. Optimal is tropical granulate, fish food or shrimp food. As a newcomer to Triops breeding, you should not be surprised or frightened if a large Triops eats its conspecifics. Cannibalism is normal in Triops and is particularly pronounced in the American species Triops longicaudatus. Cannibalism can be counteracted by feeding the Triops a protein-rich and balanced diet. The majority of Triops are females. Males, on the other hand, are a rarity in ten percent of the population. The average life expectancy of Triops is between 30 and 90 days.

Reproduction

Triops become sexually mature after about two weeks and start to lay eggs permanently in the sand. They are encystised embryos in the gastrula stage and can rest in the soil for many decades. They remain dormant until a new flood triggers the re-hatching of the nauplii. These extremely resilient cysts are able to survive for a long period of time outside their native waters. In the Triops species Cancriformis, a period of 27 years of drought is considered proven. Triops reproduce both sexually and asexually. The hermaphroditic gland is used for self-fertilisation (autogamy). During the growth phase, Triops go through numerous moults. The largest animals reach a length of up to eleven centimetres. In the species Triops cancriformis, the average length including the tail is between six and eight centimetres.

Triops longicaudatus is the most popular species, but not the only one

In domestic breeding, the most popular Triops species is the American Triops longicaudatus. Most beginners in Triops breeding start their first breeding with Triops longicaudatus. The distribution of this species extends from the north of the American continent through the Caribbean to South America. The light brown colour of the carapace gives the Longicaudatus its characteristic appearance. The Triops grows to a size of five to seven centimetres. It is smaller than the European species Triops cancriformis. Triops longicaudatus needs a temperature of 25 to 28 degrees Celsius.

Other Triops species are:

• Triops longicaudatus red
• Triops cancriformis
• Triops granarius
• Triops australiensis Ayers Rock
• Triops newberryi
• Triops beni kabuto ebi albino
• Triops longicaudatus intermedius, also called T. Australiensis Queensland
• Triops granarius numidicus
• Triops mauritanicus
• Triops simplex
• Triops baeticus
• Triops emeritensis
• Triops gadensis
• Triops vicentinus
• Triops maximus
• Triops multifidus
• Phallocryptus fahimii (discovered in 2017)