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Rearing Suggestions
Once you have adult Triops producing eggs, you can theoretically keep a propagating culture forever. The desiccation-resistant eggs can lay dormant for decades before hatching, and one can merely stick them in a ziplock bag in the dark until you want to hatch the eggs again. For optimal hatching, there needs to be at least 30 days between when the eggs were laid and when you rehydrate them. To get a new culture going, I suggest taking dry dirt samples from any nearby locations. The soil that they are adapted to is the "reddish" soil found in the deserts of the southwest. Thus, dark, humus-laden soil is probably not appropriate, though it is better than nothing. We use about 500 ml of dry soil in a 10-gallon, all-glass aquarium (see Figure 5).
Use "aged tap water" for hydrating the soil. You can age the water by letting the tap water sit for about 4 days with an aquarium bubbler (e.g., an airstone) in the tank on "high." We find the best hatching happens when you simulate a "flash flood." Thus, take the water out of the 10-gallon aquarium, put in the dirt, and then pour the water back in a "vigorous" fashion. Put the airstone back in on low-air. When the eggs hatch, they hatch as nauplii. We feed the nauplii a baker's yeast and algal fish flake food solution (about 40 ml of solution, the solution being made of 500 ml aged tap water and 2.5 gm of dried baker's yeast and 2.5 gm of finely ground flake food for algal-eating fish, such as spiralina flake food - see ads on side bar to buy algal flake food). Feed them this for the first 2-3 days. After this, you should see juvenile Triops on the bottom of the aquarium. They should leave trails in the soil, which are little lines that are indicative of their "rooting" through the soil material (see above). At this point, you can start switching over to ground goldfish food or freeze-dried brine shrimp (see ads on side bar to buy both foods) as a food supplement. Make sure you get the "sinking" variety of goldfish food (see side ads), as the floating variety won't work. The amount you give them depends on the numbers you have and their size. When they are small (within the first 3-7 days or so), they don't take much (say a pinch between your forefinger and thumb). If you are using freeze dried brine shrimp, make sure you break the pellets up rather than adding a full pellet (or cube). After that, you will have to increase it a bit. I can't tell you exact quantities: you will have to experiment a bit. Do note that if you add too much food, it will start to degrade, which can create a large bacterial build up that can kill the shrimp. One additional thing to consider: when the Triops start to get large (in a week or so), they will start to burrow into the soil quite a bit, making the aquarium uneasy to impossible to see into. I used to siphon off most of the water each day to check on the status of my Triops, and then re-siphon it back into the tanks. Although the cloudiness is "non-optimal" from our perspective (because of the lowered ability to see the Triops), it does indicate that the Triops are doing well. At this point, they can eat the goldfish food straight, without grinding. Add only a few shakes per day. The water temperature should be kept between 25 and 30 C, and to get maximal growth, you should keep a light on the aquarium at all times. Many 10-gallon aquaria come with hoods, which we used for both heat and light (see figure 5). Here is another suggestion from a colleague of mine, Dr. Stéphane Plante [Research Centre of Forest Biology (CRBF) Laval University Quebec, Canada], who also consulted Charles Hannum: "Dear Dr weeks, I have finally solved my problem with the rearing of Triops nauplii obtained from eggs produced by adults in the laboratory. The death of the lab larvae is essentially caused by some bacterial infection in recovered natural soil or in other humic soil (black soil, mud, sand with dead algae, etc...). I now use some crushed chips of the coconut external shell (these dark brown coconut chips are sold in compressed bricks (~9$ each) in large pet shops and they are used for vivarium soil for reptiles). If coconut bark is not available, you may use the external bark of some leafy trees (e.g., maple, oak etc...) as detritus for Triops. Don't use the bark of coniferous trees. The crushed coconut or the leafy tree bark debris are mixed with spring water (ozonized or not, max 200 ppm of total mineral salts, the best is 130-160 ppm of salts) and the pure dried (or not) Triops eggs are added to this medium. After a soaking of 12-24 hours, in strong light at 18-25ºC, the coconut debris (or bark debris) will sink to the bottom of the 500 ml jar. The newly hatched larvae are fed with very small amounts of pure powdered Spirulina alga crushed in a spoon of spring water. A few drops of crushed Spirulina are then deposited (with a small dropper) among the coconut debris, in 2-3 places on the bottom of the jar. The larvae feed on this algae (they have a green digestive track) and they easily reach the juvenile stage (~5 mm long). Other algae are added only when the green spots on the bottom of the jar are totally consumed in order to avoid bacterial pollution. When the larvae become juveniles, they are then fed with a few, very small pieces of TetraMin flakes (aquarium fish food) placed in a few places among the detritus. The juvenile Triops may now be transferred to a new soil made with pure peat moss or leafy tree bark debris (external bark of the tree). I had also observed that nearly 100% of the non-dehydrated eggs of the adults will hatch if they are kept in water in an open jar, even if the jar is in the dark, at room temperature. The freshly laid eggs should be stored in a refrigerator to prevent their hatching or they must be kept in anoxic water at room temperature before the dehydration 10 days after the laying... Finally, I have successfully raised Triops larvae at 18-22ºC rather than 25-30ºC,and these cool temperatures didn't kill the larvae. The lab larvae are essentially killed by bacterial spikes in overfed conditions or by using media made with soiled detritus." I haven't tried the above procedure, but Dr. Plante assures me that it works well! Here is another suggestion by Dr. Plante: "I raised with more or less success the Triops longicaudatus larvae. Nearly all my trials with powdered spirulina and powdered TetraMin flakes (fed as a colloidal suspension to larval Triops) were failures, even with a constant warm temperature of 26ºC. Again, I have not specifically tried these suggestions, so I cannot confirm these results in my own lab. However, they do sound intriguing! Suggestions for experiments that can be conducted in the classroom
Links
The Clam Shrimp Information Page - Information, movies and pictures of Triops' close cousins! Crustacea.net - Information about all known crustacea The Large Branchiopod Bibliography - A list of many large branchiopod original publications from the 1800's to present (exclusive of papers on Artemia)
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Fig. 5 - Triops
aquaria
