Thursday, November 6, 2008


For science this month, we decided to grow some Triops longicaudatus (Sold in stores as Triops.)

Members of the order Notostraca (colloquially referred to as notostracans, called Triops, tadpole shrimp or shield shrimp) are small crustaceans in the class Branchiopoda. Triops have two internal compound eyes and one naupliar eye in-between, a flattened carapace covering its head and leg-bearing segments of the body. The order contains a single family, with only two extant genera. Their external morphology has apparently not changed since the Triassic appearance of Triops cancriformis around 220 million years ago. Triops cancriformis may therefore be the "oldest living animal species on earth." The members of the extinct order Kazacharthra are closely related, having been descended from notostracans. -Wikipedia

The tadpole shrimp (scientific name = Triops longicaudatus, which are in the order Notostraca in the class Branchiopoda) inhabits freshwater, ephemeral ponds ranging from 50ÂșN latitude in western North America through Central America and into South America. In the U.S., Triops are found in desert habitats (see Figure 1). They live in small pools that accumulate after flash floods in the summer. Since these pools are rather short-lived, the Triops consequently have short lifespans, completing their life cycles in a mere 20-40 days! -The Triops Information Page

Set Up

  1. The first thing is to get all the items you need- If you have a kit, you should only need a light (for keeping the water warm) and container. (Some big kits come with one.)
  2. For the light, we used a desk lamp with a 50 watt bulb; you should check your instructions as too how hot the water needs to be though. (Mom's note: we used a reflector bulb, which threw more light/heat on the tank and less into the room.)
  3. For the container and water, start with a small one (you'll need to switch to a bigger one when they get larger) and fill it leaving 1 inch at the top with spring water. You also want to cover some of the tank with some aluminum foil to give them some shade.
  4. Before you put the eggs in, you need to put nutrients in. Most kits come with them, but if not, you can make your own with leaves.
  5. After 24 hours, put the triops in the container.
  6. The triops will hatch 18 hours after you put them in. When they do, you shouldn't feed them for another 24 hours.
  7. On day 2, start feeding them the food pellets. (These will come in the kit.) Give them 1/2 of some crushed green and brown pellets, and continue until you think they can eat a whole pellet on their own. (Usually by day 4.)
  8. When the start eating whole pellets, switch between green and brown.
  9. By this time you should switch them to a bigger container, as they won't be able to grow in the small one. We got a container that was three times bigger than the smaller one, which has worked. (If you want them to lay eggs, put 1/2 an inch of sand at the bottom.)
  10. Just keep feeding them until they die. If they laid eggs, let the water evaporate and start over with the new batch.

When we started the triops, we also started a log of what they were doing. This is it:

Day 1:

11:00 AM: We added our Triops eggs to the water we prepared in a plastic container.
5:00 PM: We added more water to replace the water that evaporated.

Day 2:

10:30 AM: Our first Triops hatched!!
8:00 PM: we spotted another Triops swimming around (We never saw him again, and presumed that the bigger one ate him.)

Day 3 :

9:40 AM: We fed the Triops. (A quarter of one of the green and brown pellets that came with the package.)

Day 4: (We forgot to take notes on Day 4.)

Day 5:

10:20 AM: Fed her. Same as before.

Day 6:

8:50 AM: Fed her (same as Days 3 & 5) We noted that at this point, our remaining Triops was 3/4 of an inch long.
11:30 PM: We used a pipette to suck up some sludge that was growing inside her container.

Day 7:

3:00 PM: We fed her (2 crushed pellets this time)
3:40 PM: We moved her to a bigger container.
Also, on this day, she molted!

Day 8: (We forgot to write down the time)

Fed the Triops (We started feeding her twice)
We noted that her movement has slowed down a bit.
Day 9: (We didn't write down the time today either.)

We fed her a green pellet. (We're not sure what the difference between a green pellet and a brown pellet is.) (Mom's note: green is vegetable, brown is meat. Mmmm.)

We also took an awesome video of her swimming around with our new digital microscope!

That's all we've done so far, but we'll have regular updates as things progress.


ToyOps: made the kit we bought
A Triops Classroom Guide: Lots of useful info and experiments (PDF)
My Triops: Hobbyist Stuart Halliday's site from the UK
Microscope Projects with Triops: Good general microscope site!


Anonymous said...

How can you tell if you triop is a boy or girl?

Also when they lay eggs in the sand, can you transport the older triops into a different tanks including the water and put the eggs in the same container, just fill it with different water later?

Anonymous said...

actually triops are boys AND girls so almost all of the triops will make so eggs

Anonymous said...

well no, most triops are females, which can reproduce without males, however there is sometimes males, which if im right in thinking you can tell are male byt the difference in the body shape, well the hard shell and the male has a shorter tail.....

anyway! im growing a triops right now in a 25 litre tank, he is growning great!!

Anonymous said...

does anyone know if you can take a triops thats been growing in a small tank and move it to a big one with fresh water

Kathy Ceceri said...

We have moved our triops to a bigger tank. It might be a good idea to pour as much of the old water into the new tank as you can (as long as its clean) to avoid a sudden shock to the system.