Fish Egg Science

This next project/experiment we’re doing is a real-time comparison of classic Sea Monkeys versus their prehistoric crustacean counterparts- notostracans (more commonly called Triops). Two days ago, my son and I put distilled water in three tanks. In tank 1 we also added the water purifier that came with our Sea Monkeys. We let the water sit for a couple of days to acclimate to room temperature and let any excess chlorine boil off. I’m not posting any pictures yet as we just added the eggs tonight and there’s not much to see. A summary of the three tanks follows:

1. Tank One is the plastic tank that comes with the Sea Monkeys. If you’ve ever had any Sea Monkeys, you’ll remember the classic tank with the blue or red lid with the built in magnifying glasses on the sides. These certainly come in handy as Sea Monkeys are tiny after hatching and don’t get very big anyway. We used distilled water and added the purifier that came with the kit. We added the entire packet of “Instant Life,” or the Sea Monkey eggs in diapause. Amazingly, within the first minute, we could actually see the very tiny Sea Monkeys hatching and swimming around the tank.
2. Tank Two is the plastic tank that came with the standard Triops kit. It’s bean-shaped and about four inches high, 8 inches in length. We filled it with about three inches of distilled water. No purifier was added. We added 14 Triops eggs tonight. The eggs used were leftover from a hatching I did last spring.
3. Tank Three is a plastic Rubbermaid food bowl, about eight inches square and filled with about the same amount of distilled water as Tank Two. No purifier was added to this tank and again, we added 14 Triops eggs.

Right now, the plans are to feed the Sea Monkeys the powdered food they came with. We want to vary the food between Tank 2 and Tank 3. Tank 2 will be the standard food pellets that came with the Triops and Tank 3 will likely be dried vegetable matter such as lettuce, spinach or cabbage. I hope to be able to document the growth in the three tanks as our project progresses. Stay tuned for updates…

Family: Triopsidae, Order: Notostraca, Class: Branchiopoda, Subphylum: Curstacea, Phylum: Arthropoda, Kingdom: Animalia.

In simpler terms, they are crustaceans. They look almost like small horseshoe crabs but with three eyes. They are sometimes called tadpole shrimp or more formally, notostracans. One of the most interesting facts about this order of animals is that their external morphology has not changed in roughly 200 million years. This means the Triops you see today are the same creatures the dinosaurs in the Triassic period observed. Some scientists believe they are actually the oldest living animal species on Earth.

Another interesting fact: Triops don’t have antennae like many crustaceans. What may look like antennae are actually their first pair of legs. These do act as sensory organs however, and have evolved to serve a similar purpose.

Every thoracic segment from the thirteenth back will have 4-6 pairs of legs. That’s right, this creature can have as many as 70 legs total. No other crustacean comes close to this.

How do you tell male from female Triops? The only exact way would be to look at their eleventh pair of legs. In the females, this pair has evolved into a round egg capsule to carry their eggs. In the males… nothing. Just a regular leg.

Having three eyes, one might think that Triops have an excellent sense of sight. This is only partially true. They don’t use their eyes to find food, but their eyes do help orient them toward or away from the light in their environment. An interesting experiment to demonstrate this would be to observe them in their tank in a normally lighted room, then turn the lights off and use a flashlight to light the bottom of the tank. The crustaceans will then reorient themselves thinking the bottom of the tank is the top.

Life Cycle

The most interesting study these creatures offer is their life cycle. In any Triop pool, there are relatively few males. In the northern hemisphere, the ratio is often less than one in 100 Triops being male. For this reason, most of the females’ eggs are unfertilized; however this makes little difference in their hatching rate.

The eggs are enclosed in a strong thick shell and can withstand some very harsh conditions. The eggs can withstand temperatures from below freezing to about 180 degrees Fahrenheit (80C). They can be eaten by a frog or fish, digested, expelled and still hatch. They can exist in a diapause state for many years, some scientists think for decades. The hardiness and longevity of these eggs have contributed to the widespread regions in which Triops can be found.

Some of the eggs will ultimately wind up in a pool with suitable conditions for hatching, and the larva will hatch about a year later. Within about two weeks, the creature will have molted about 12-14 times and will thus be an adult. The Triop will molt about 40 times before it reaches sexual maturity.

The life span of Triops in the lab (or your aquarium) and in the wild are about the same. Most will live between 50 and 90 days.

If you’re interested in trying out some yourself, you can pick up the Triassic Triops Deluxe kit here.

In keeping with the recent theme of this website, I wanted to review another one of my favorite live animal kits and take a look at GeoSafari’s Ant Factory. Many folks might errantly call this an “ant farm” but it can’t officially be called one as that is a tradmarked toy from Uncle Milton. Regardless, it’s pretty much the same thing even though it’s simply called an “ant habitat.”

I opened one of these up to check it out a few weeks ago and was pleasantly surprised with how solid it feels. Many of us are familiar with the Uncle Milton vintage ant farms and will remember just how light weight they felt, and that the white substrate used for the ants to tunnel in feels like a semi-natural Styrofoam. Not so with this GeoSafari Ant Factory. The substrate used in this one almost feels like a dirt/sand mix and I’m sure it’s much more similar to the ants’ natural environment.

This kit is 9″ high by 15″ wide and comes with a nice 24 page instruction book. Overall, it’s a very solid feeling ant habitat and if you’re ready to give something a try that’s not from the Uncle Milton line, I can wholeheartedly recommend this one. At about $25 US, it’s a little more expensive but I felt worth it. By the way, it also comes with a certificate to receive your ants by mail.

Since I just wrapped up the last post of our Great Tadpole Experiment I thought the next toy review I do should be of something related. As far as I know, Uncle Milton’s Planet frog is really the only kit dealing with frogs that I know of. There are lots of live animal kits for ant farms, Triops, Sea Monkeys and hermit crabs but just this one for frogs.

As far as educational toys go, this is a decent one. The kit is basically a small plastic aquarium with a certificate to send off to receive a live tadpole by mail. If you live somewhere that you can’t easily catch your own tadpoles this is a pretty good way to go. As far as the plastic aquarium goes, it’s not too solid but it’ll hold up well enough under normal use. If you have a curious cat you may have to put this somewhere that he can’t get to it, or else do what my son and I did and put your tadpole in a standard fish tank. Even then my cat was determined to make a tasty treat out of our frogs so we had to keep a heavy book on the tank lid.

If you’re in the market for some science kits, check out Atomic Elephant Toy. You’ll find some great prices on various live animal kits including the Uncle Milton Planet Frog. And if you’ve never raised Triops, check out their Triops or Aquasaurs. These are some amazing creatures.

May 31st, 2008, 41 days after we started our great tadpole experiment, we had 10 frogs ready to be returned back to the pond where we found them. Since my son and I had no real prior experience catching and raising tadpoles we thought our experiment was pretty successful overall. We started with four tadpoles, then caught six more and raised them all to be mature frogs in about 6-7 weeks. We debated on keeping a couple of the larger frogs as pets but decided they would be happier back in the pond where we found them. Plus, I was going out of town for a couple of weeks and no amount of pleading could ever convince my wife to feed these guys live insects even once, much less for two weeks. The following are the last pictures we have of our frogs and of us returning them back to nature.

The frost frog to get back to his natural habitat…

Three happy frogs about to go home. Two more on deck…

Matt the neighbor and Matt my son…

A big turtle we hope doesn’t eat our newly released frogs.

Okay, so I recently wrote about what we fed our tadpoles and the next logical question is what should you feed your new frogs? First I’ll tell you about the research I did and what I found out. Then I’ll tell you about what our frogs ate. All the frog experts say the new froglets will happily eat small insects. Okay, this sounds easy. On about day 30 of our experiment the frog/tadpole inventory in our tank was: 4 frogs (totally breathing air, no tails), 3 froglets (all four legs, but still a significant tail, and breathing water and air), and 3 that were still completely tadpoles.

So my son and I went out and bought a cricket holder and about three dozen crickets. We dropped a couple of crickets in the tank (on the log so they wouldn’t drown) and thought the new frogs would jump up there and just gobble them up. That didn’t happen as the crickets were about half the size of the froglets. So now we have two cricket pets jumping around the tank for a couple of days, and four frogs that must be getting pretty hungry. Being the humanitarian that I am, I couldn’t bear to see our frogs starving so my son and I went out in our backyard. He called it “frog food hunting” which is as good a name as any for what we had to do every day for the next week. The first day we found a dozen or so roly polies, a couple of beetles and some centipedes. I didn’t think they would eat the beetles as their exoskeletons are pretty hard. And the roly poly bugs have a fairly hard shell as well. But we put them all in the tank anyway. The centipedes went first. The frogs loved them. To my surprise, the roly polies were eaten pretty quickly as well. The two beetles joined the crickets and were never touched.

The next day we caught a few more roly poly bugs and a couple of earthworms. The earthworms were easy prey and the frogs loved them. And again, the roly polies were gobbled up fairly quickly. The crickets had drowned and were sucked into the filter.

So there you have it. Here’s the list of what our froglets ate and my best guess of how they preferred each:

1. Centipedes (they loved them all- both small and medium sized)
2. Earthworms (also loved, but need to be fairly small or else you can cut them into pieces)
3. Roly Poly bugs (the bigger the frogs got, the more they ate them)
4. Beetles (these weren’t eaten at all)
5. Crickets (these weren’t eaten, but I think as the frogs grew they would have loved them)

The below are a couple more pictures of our Great Tadpole Experiment as the frogs were starting to mature. The next post will conclude the experiment and I’ll write about letting them go.

Froglet and Tadpole

Three hungry frogs and three roly poly meals.

I’ve seen a lot of traffic stumble upon this site by searching for some variant of the question “How can I tell what kind of frogs my tadpoles will become?” So apparently a lot of folks out there have caught tadpoles this spring and are doing the same tadpole project that my son and I have been doing. If this is the case, I’ll answer the subject question below– at least how it is in our case.

What should I feed my tadpoles?

For the most part, our tadpoles lived very well on flake fish food for the first several weeks. As we had 10 tadpoles I did feed them a fair amount (probably a bit more than I would have fed 10 fish in the tank). At least once or twice a week we did give them some leafy vegetable (either spinach or a dark leaf lettuce). I did come across some sources recommending that leafy vegetables be boiled before feeding as it would soften it up a bit. I suppose this would happen but in our case we never went through the trouble to boil anything.

To keep the leafy vegetables from getting sucked into the filter we placed the leaves under a small decorative rock on the opposite side of the tank. This seemed to do the trick and we often observed the tadpoles munching on the spinach or lettuce. It would last a day or two in the tank until the tadpoles had eaten enough of it and the remaining shreds would ultimately get pulled into the filter.

I should note that for the first six weeks we did have some water plants from the pond we found the tadpoles also in the aquarium. These had a thick root system that might have also given the tadpoles something to munch on. I can’t say for sure, but if you’re not having much luck feeding your tadpoles flake food and spinach, you might try putting a couple of live plants in the tank. It may or may not help them nutritionally, but I’m sure it wouldn’t hurt.

Okay, so I just got back into town after a long weekend. I wasn’t quite sure how our ten tadpoles would do but I left them some fresh lettuce and they made it just fine. In fact, two of the tadpoles are now officially froglets! The first two pictures are from a few days ago, as the largest tadpoles were just developing their back legs.

The next picture is of the second largest froglet (taken last night, Day 21 in our tadpole habitat). Note the legless tadpole in the picture. This little guy was one of the six introduced on day 7. I’m a little surprised at how fast the first four tadpoles we started with have metamorphosed compared to the second generation- some of which still don’t even have any back legs yet.

I completely cleaned the tank tonight and took as accurate of an inventory as I could count. So here’s the current tank roster: 2 froglets (front and back legs, breathing air and water), 4 with back legs only, and 4 with no legs yet. They all seem to be growing well though. The smallest ones we added on day 7 are now much larger.

One interesting note is that the above pictured froglet absorbed most of his tail in one day (see picture below). This was pretty surprising to me as I thought it would take at least a week or so. I don’t think the two froglets have completely lost their gills yet, but from my observations tonight they seem to be spending about half their time with at least their head out of water. So far the tadpoles have existed on a diet of flake fish food and green leafy vegetables. Tonight my son and I went insect collecting in the back yard to catch something that the froglets might eat. The only insects we could find were a few pill bugs (roly polies), a very interesting juvenile centipede, a beetle and a couple of small earthworms. The earthworms were eaten but the other bugs haven’t been touched yet. I’m not sure if the new frogs’ digestive systems will be tough enough to handle the exoskeletons of the pill bugs or beetle yet but I guess we’ll see. The first picture below is of the froglet above- notice at least half of his tail has been absorbed.

Next is the other froglet. His tail is still significant although it’s not seen completely in this picture.

We’re going to have to pick up some crickets or grubs to start feeding the frogs soon. Stay tuned for updates on the other six as they start to go through their metamorphosis as well. If you’ve enjoyed reading about our experiment, be sure to check out my store for science toys. We’ve got the Uncle Milton Planet Frog habitat, and plenty of other live animal kits that are just as fun.

Okay, I was almost able to get new pictures of the four-legged tadpoles/froglets last night but alas, they were too fast for me. Plus, it’s always difficult taking pictures through the glass walls of the aquarium. Half the time the flash reflects too much, and the other half of the time it scares the little guys to the other side of the tank. I’ll try again tonight as their metamorphosis is really something to behold! I’ll try and update this post with pictures later…

Day 16 and the tadpoles are all happily growing and swimming about the tank. Here’s the twist to this morning’s observations. The two largest, who have had rudimentary back legs for a while now, still only have their back legs. Though they are filling out nicely. But… two of the smaller ones who just sprouted their back legs last week have already started on their front legs. It is very curious as I would have thought the back legs to become more formed before even any hint of the front legs. It does make me wonder if they are the same species of frogs. And speaking of that…

I did a little research on salamander tadpoles and came across a teacher in the pacific Northwest who did a nice job of documenting her classroom’s tadpole project in 2007-08. It made me wonder if any of our tadpoles might be salamanders instead of frogs. I’m not completely sure but I think they’re all frogs for the following reasons: 1) We caught them in three different locations of the same pond, but the locations were in close proximity to one another, 2) Our tadpoles all have similar markings, 3) They are of varying sizes but that may be a factor of age. So I’m pretty sure we’re going to get frogs. With the different rates of growth though, I am excited to see if we get different species. Stay tuned, we should know in a couple of months!