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Frequently Asked Questions about Triops

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triops three eyes

Triops have three eyes

General FAQ

What are Triops?

They are small freshwater shrimp that grow from tiny eggs that you can buy from most Pet or Toy shops. They are often called Tadpole or Shield Shrimp.

Scientific name is Triops longicaudatus (TRY-OPS LON-GA-CAW-DA-TUS), by far the most common species you’ll find on sale in shops as they come from America. Triops cancriformis (TRY-OPS CAN-RIFF-FORM-IS) comes from Europe and grows larger and lives longest!

What do they do?

They swim a lot, eat a lot, grow even more and lay eggs. They’re fun to watch with their antics as they swim cartwheels looking for food. Some teachers even use them in the classroom to teach the science of life.
Other people use them as a ‘beginners guide to raising fish’ in an Aquarium. Because if you can look after a Triops for a few months then maybe you might like to look after fish in a big tank!

How do they breath under water?

They are very ancient creatures and long ago evolved the ability to breath with their feet! Fish have gills in the sides of their head. Triops have their gills in their legs!

Do they really have three eyes?

Yes, Triops have been around a long time and have evolved some strange things. One of their eyes sense light so it knows which way is ‘up’. Whilst the other two eyes look out for predators or snacks.

How old are they?

Very old! In fact Triops (Triops cancriformis) have been around for over 220 million years. So they’ve seen giant dinosaurs like Tyrannosaurus rex and Stegosaurus come and go.
They were swimming in pools when giant mammals like the wooly mammoth roamed the Earth.
When our ancestors lived in trees, there the Triops were in their pool, swimming and eating.
Today they are known as the oldest living species of animal in the World. No wonder they’re often called or living fossils!

Where do they come from?

Whilst toy shops sell them, they actually grow naturally in the wild on virtually every country in the World. Scotland, Russia, USA, Africa, India, Iceland, Japan. You name it they are there!

Are the eggs I buy taken from the wild?

All eggs you buy are collected from hand reared Triops in tanks and are not harvested from the wild. In some countries (like the UK) Triops are actually an endangered species so taking them from the wild would be very wrong.

Are they easy to rear in my home?

Yes, they are very easy to raise. You just need some eggs, a couple of litres (pints) of water and a container of some kind.
You just add the water to the eggs, keep them at room temperature near a bright light source and watch them hatch out.
See our Container page for ideas.

What about feeding them?

Most kits you can buy in the shops come with plenty Triops food. But you can feed them virtually anything plant related. See our Recipes page for some of the things Triops owners have thought up. You’ll be surprised!

Is it expensive to keep them?

Not at all. For around £4 pounds (US$7) you can buy the eggs. Then a glass or plastic container needn’t cost more than another £4 (US$7) if you wanted to splash out and get one specifically for raising Triops. You don’t need to spend more than another £2 (US$3.5) on bottled water. So for £10 (US$18) or less you’ve got a complete set up.

Of course you can spend more if you want to keep the Triops in the lap of luxury. Some people buy Aquarium tanks, air filters and special food to ensure their Triops live the high life!

How long do Triops live for?

If you keep them in good health then they can live as long as 14 weeks. Though 8 weeks is typical. (Triops cancriformis lives the longest)

Why so short a lifespan?

Because that’s how they have evolved. In the wild they hatch out of their eggs within 24 hours of a pool of rain water forming over them. They then eat and grow and eat again to grow as quickly as possible before the pool of water evaporates. It’s amazing watching how fast they grow. Within 7-10 days they’re fully adult and can lay 10 eggs a day. They continue to grow in size every day.

How big can Triops get?

Triops can grow pretty big. Some Triops have been measured at 11cm (4inches) in the wild (we don’t include their long tails when measuring their length)!
Typically you can get them to grow 6-8cm (2-3inches) in length in a tank. Triops cancriformis species grows the biggest. Triops owners like taking pictures of their wee creatures.
See the Gallery section of pictures and movies of their pets.

Can a Triops bite me?

No. Their mouth is very small and there is no chance of it even nipping you in the slightest.

Can I hatch out the eggs they lay?

Yes you can. You just drain off the water, let the eggs dry out really thoroughly for a few days and then add some water again! You need never run out of eggs again!

Are there different types of Triops?

Yes, quite a few.
Most commoningly sold in the shops is the American species called Triops longicaudatus which looks rather golden in colour. It grows up to 8cm (2 inches) and lives for up to 8 weeks.

Then there is the Triops cancriformis species which is found throughout Europe and can grow up to 11cm (4 inches) and lives for longer (14 weeks) than its American cousin and is more green-brown.

There is an Australian species called Triops australiensis which is rarely seen outside its country and is more copper-blue in colour.

There are about 10-15 different species in total. But the others species are hard to get hold off. See our Triops Species section for more detail.

Ok, I’ve got a kit. But what’s the best way to get started?

Best way is to read the Quick Setup page.
You’ll be successfully hatching Triops in no time!

Hatching FAQ

What is ‘detritus‘?

This is the name used in biology for organic waste material from decomposing dead plants. Typically dried up leafs, etc.

What is detritus used for?

When Triops hatch out they require very small food to eat, the detritus contains micro-organisms called infusoria which hatch out when added to water. The Triops larva feed off this to survive the first 3 days. Later they need to eat bigger food that you provide, like the brown and green pellets provided by some kits. The detritus also breaks down in the water and provides minerals for Triops to grow.

What is this water conditioner bag I’ve got?

Some Triops kits supply a ‘tea bag’ like package of detritus (small pieces of plant matter). It’s only there to provide food to hatch out the young Triops. The detritus contains the eggs of infusoria which hatch out and the young tiny Triops feed off these microscopic animals. The detritus also breaks down and provides minerals for Triops to grow. Once your Triops are more than 4 days old you can remove it if you wish. But don’t throw it away. Let it dry out in a warm spot and you can reuse it if you plan to hatch out further Triops at a later date.

So after 3 days I can remove the bits of detritus?

Yes. Some Triops kits come with the detritus contained in bags, so you can simply dry it out and use it again. Loose detritus can be thrown away. If you ever need more simply collect a small dried leaf from outside (pick one with no bird droppings) and tear it up into small pieces. Do not use a fresh green leaf.

What is infusoria?

This is the correct name for the micro-organisms which grow out of the detritus and is eaten by the Triops.

Why do they really need constant light in the first 72 hours?

Two reasons.
One, the eggs are triggered to hatch out if they get wet and have a strong light source on them. No light, no hatching.
Two, when the infusoria hatches out from the detritus they gather towards the light source. This is usually the water surface in nature. So we need a light above the water. When the Triops hatch out, they move towards the surface and can therefore eat the infusoria which they expect to find there.

If the Triops don’t get enough to eat in the first 3 days, they very quickly starve to death.

A simple Mains table lamp with a 40W-60W bulb a few inches above the water is all that is required.

My Triops Kit say don’t add anything into the tank. Why?

They say this so that you’ll have more success in hatching out the Triops.

Triops like water with low mineral content in order to trigger them to hatch out. By adding things to the water like sand, plants, ornaments then you could possibly reintroduce minerals or chemicals to the water which will cause the Triops eggs not to hatch.

You’ll find using a substrate like coral sand that has been very well rinsed in a bucket is fine. Just ensure you never use soap or any detergent in any of the tank items. You’ll kill the Triops.

None of my Triops hatched out. Why?

This is always one of the following reasons.

a) You didn’t provide pure enough water. Triops eggs need very pure water to trigger them into hatching. Bottled water can have too much minerals in it. Look for the ‘Dry Residue’ amount on the label. If it is more than 90mg, get a purer source of water. Distilled or de-ionised water used for cars or irons is perfect.

b) You didn’t have a source of light above the water on constantly for the first 72 hours then they will not hatch. The Triops eggs need light to trigger them into hatching.

c) You didn’t have the water temperature at around 22°C (±5, If it is too hot or too cold, then the Triops eggs will not hatch.

Some of my Triops hatch out and within a day or so they all died! Why?

This is usually due to the following reason.
You may have used too much water. The more water you have in the tank, the more the infusoria is diluted and so the tiny Triops have difficulty finding enough to eat in the crucial first 72 hours. So they simply die from lack of food.
I recommend that you only have about 5cm (2″) of water column. In a standard Triops 1 litre kit this is usually about half full. You can add the rest of the water once they’re over 3 days old.

Why didn’t they all hatch out?

Triops are very clever, their eggs are designed not to all hatch out at once.
This saves them all from dying if for example the pool gets filled by just a passing shower and would only last a week or less. If they had all hatched out, they’d all die. Some eggs will not hatch out in the pool until they receive a second dose of rain water. So by staggering their hatching rate in this way they maximise their survival. One reason why Triops have survived over 200 Million years!
See Eggs and Babies article for more detail.

Why do I need to use pure water?

See the question ‘None of my Triops hatched out’
You don’t need pure water but you will get more Triops hatching if you do.
Triops in the wild come from temporary pools of rain water, so they have developed a special survival technique.

A pool of rain water may dry out at any time, so to ensure that Triops hatch out in optimal conditions, the egg senses the amount of minerals dissolved in the water. The less minerals the fresher the water must be. A large pool of water will also stay fresher for longer than a small puddle for example.
See the Triops egg page for more detail.

What triggers the eggs to hatch out?

There is a more indepth article on the survival tricks the eggs have developed over millions of years.
See See ‘Eggs and babies’.
But to summarise, if the eggs hatched out all at once then if there was a problem (hot spell, predator, etc.) then the whole population would die out.

So only a few do at once. The first main trigger is the egg needs light on them to ensure the new born Triops can swim to safety and is not say buried under mud!

Second main trigger is that the egg needs to be wet, but not just any old ‘wet’ water. The egg detects the amount of dissolved minerals in the water. Fresh rain water is usually pretty pure, this indicates to the egg that the rains have just come and the temporary pool will hopefully last for the few weeks the Triops needs to grow to adulthood and lay more eggs. Water with minerals in it usually indicates that the pool has been around for a while and so could dry up soon.

This is why people often discover a few weeks into raising Triops and performing water changes that new Triops come along! These eggs think fresh rain have come! The amazing thing is that each egg is different, they all appear to have varying degrees of triggering points. Some will not hatch out the first time around but will maybe the 2nd or 3rd time it’s wetted.

Other trigger points are that the egg needs the water to be warm enough. Too cold and it’s not going to be able to grow fast enough. Also some eggs need to be dried out for a while. This ensures it will hatch out the next time it rains. This may be in a few weeks or even a few years!
Triops eggs can keep for up to 10 years!

I’ve hatched out my Triops. What are these other critters amongst them!

Most commercial kits get their eggs from in America and they bred Triops out of doors in ponds. So the eggs collected often have other pond creature eggs. Think of it as a bonus!
See a Pond Life web site to try to identify them.

Caring FAQ

How often should I change the water in my Triops tank?

As often as required. It’s hard to say as everyone’s tank is different. But if it smells then it probably needs changing.

If you feed too much or don’t have a filter fitted to the tank then you’ll need to change some of the water daily.

Don’t change all the water or you may kill your creatures. Change about 25% maximum a day. Make sure the new water is kept at the same temperature as the tank water. Sudden water temperature changes could harm your aquatic pet.

What is the minimum depth of water I need for keeping Triops?

Whilst Triops need around 2 litres of water each to ensure it has enough oxygen and a decent amount of area to move around in. It doesn’t spend a lot of time as an adult swimming to the surface and it can’t crawl or jump out so you can get by with only a short water column. Say around 10cm (4 inches).

I want to put my Triops in my big freshwater aquarium tank with my fish.
Is it safe to do so? Will my fish harm the Triops or will my Triops harm my fish?

Yes you can put Triops in with tropical freshwater fish. Obviously if you’ve got big fish (anything over 3 inches in size) like Chiclids then they may decide that the Triops are a meal and eat them! But most smaller fish will ignore them.

Even very small fish like Neon tetras or Corys will be completely unharmed by them. Some people keep Dwarf African Frogs or other shrimps in their tanks and Triops do no harm to them or vice versa.

I’ve got my Triops in a small tank and I need to transfer them into my big tank. How can I do this safely?

Moving any small aquatic creature instantly from one body of water to another can seriously injure or kill it due to a process called Osmotic Pressure.
Differences between the two bodys of water may be so different that cells in the poor creature can’t take the stress and literal die.

What you have to do is remove 20% of the water from the small tank and replace it with water from the big tank. Do this daily for about 4 days. By the time you’ve done this the Triops will be used to the new water and can be moved across with no ill effects.

How soon can I move them across to the big tank?

As long as they have reached adult size (usually after 7-10 days) it should be safe to move them across using the method mentioned above.

How soon can I move them across to the big tank?

As long as they have reached adult size (usually after 7-10 days) it should be safe to move them across using the method mentioned above.

If I add Triops into my planted Aquarium will they eat my plants?

Triops have a terrifically active metabolism and so are always hungry omnivores and eat anything organic they come across (their mouth is only about 1mm wide). They are virtually blind so they just explore and try anything their feelers sense. They do nibble on roots if they are exposed. So cover the base of your plants that have a exposed roots close to the surface of the substrate with large pebbles. If your gravel is already 4mm or larger then there will be minimum problems. Plus you’d need an awful lot in an average sized aquarium to do any lasting harm. Triops do perform an effective clean up job on dead plant material!

I’m hatching out some Triops and I see small white tuffs of what looks like cotton wool on the bottom. What are they and should I remove them?

These tuffs are bacterial or fungus growths and these often grow over uneaten food. If left in the tank they may eventually kill the Triops. So prompt removal is a must and you must also cut down on the amount of food you are feeding the Triops as these growths only happen when food is left uneaten for 24 hours or longer.

Food FAQ

What is the brown and green pellets supplied with my Triops kit?

This is the Triops food supply.
The brown or black pellet is shrimp food.
The green pellet is algae.

I’ve ran out of the brown and green pellets supplied with my Triops kit. What else can I use?

You can use catfish pellets and algae wafers.
If you go to your local pet shop and look for any tropical fish food that is designed for bottom feeders then this will be fine to use.
Do not use goldfish food, this is designed for cold water fish and is unsuitable. Flake food is also unsuitable as it floats and will tend to disperse into the water and so pollute it.

Some good fish food suggestions –

Hikari Tropical Algae Wafers
Hikari Tropical Algae Wafers
Hikari Tropical Sinking Carnivore Pellets
Hikari Crab Cuisine
Aquarian Catfish Tablet Food
Tetra Fresh Delica – Bloodworm
Tetra Baby Food
Bloodworm sinking pellets

I’ve ran out of the fine baby Triop food supplied with my kit. What else can I use?

This is just very finely ground fry (baby fish) food.
Pop down to your local pet shop and get yourself some baby fry food.

What other food can I feed my Triops?

There is a huge number of alternative foods you can feed your Triops.
As they are omnivores, they’ll eat virtually any vegetable you put into their tank. Just ensure that you ‘par-boil’ it first (this means put the vegetable into boiling water for 5 minutes). This will soften the vegetable and makes it easier for the Triops to eat it.

Put a small amount of the vegetable (about the size of 2 peas) into the tank and see if they’ll eat it. At first they may avoid it as it’s new. But after an hour or less they will hopefully start eating it. If not, then take it out and try some thing different. Never leave uneaten food in the tank. It will go rotten and pollute the tank and the Triops.

Meat should only be fed sparingly. Perhaps once every other day. Very small amounts of non-salty fish or uncooked chicken or turkey. I find buying a small piece of uncooked tuna steak, cutting it up into small pieces and freezing it will supply you with enough for many weeks!

For other ideas and much more detail on how to feed your aquatic pet, please read the Food and recipes MyTriops page.

Note: Remember to not overfeed your Triops. This is the number one killer of Triops as uneaten food pollutes the water and kills the Triops. Remove any food uneaten after 3 or 4 hours.

One of the key adaptations of Triops is their amazing ability to eat almost anything available in their environment. This is important in order to maintain the rapid development needed to quickly colonise temporary ponds. It is said they requiring about 40% of their body mass in food per day! So Triops are constant detritus feeders or scavengers. They will eat anything that fits into their tiny mouth, from bacteria, algae, protozoa, lower metazoans, insect larvae, tender plant roots and shoots, and will prey on smaller Triops, fairy shrimps, and tadpoles if they come across them.

My Triops (April 24, 2024) Frequently Asked Questions about Triops. Retrieved from
"Frequently Asked Questions about Triops." My Triops - April 24, 2024,
My Triops July 3, 2020 Frequently Asked Questions about Triops., viewed April 24, 2024,<>
My Triops - Frequently Asked Questions about Triops. [Internet]. [Accessed April 24, 2024]. Available from:
"Frequently Asked Questions about Triops." My Triops - Accessed April 24, 2024.
"Frequently Asked Questions about Triops." My Triops [Online]. Available: [Accessed: April 24, 2024]
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Rick Nelson
Rick Nelson
2 years ago

I was working in the natural gas fields of southern Wyoming and came across a small depression. The water was moving with what i thought was tadpoles!!! But I looked closer and it looked like a baby horseshoe crab.l told other people about it but nobody had ever seen anything like them. For years I swore they crabs in the desert.Glad to find out just what they were.

2 years ago

Quick triops question. The closest thing I could find to sand is really fine aquarium gravel. Is that safe for them?

1 year ago
Reply to  Amanda

I use fine aquarium sand and just dry it with the eggs and rehydrate both…. basically like an egg and sand starter

2 years ago

So well written, was a joy to read – great insights, thank you

1 year ago

Can triops survive with no sand?

Dawn Sasek
Dawn Sasek
1 year ago

I am a high school science teacher looking to purchase troops online but need by end of next week. Any suggestions where to buy eggs thst I can have by next Friday? Thanks for any help,
Dawn Sasek

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