As life science teachers delve into expeditionary learning and making the classroom a more exciting place to learn, aquariums and live organisms are becoming more commonplace in the classroom. But why settle for an aquarium usually filled with one or two types of organisms when you can experience a zooquarium, a miniature ecosystem of your choosing, with a large variety of living representatives. With a reasonable amount of time, money and patience you and your students can create a biome and observe it's processes first hand.
My favorite archetype biome is a wetlands ecosystem, primarily because it's space requirements are minimal, is kind to the olfactory senses, and can be maintained on non-perishable food items. Many biological supply houses offer River Tank Systems and they are becoming popular both in educational and recreational settings, however if your budget is not suited for a $300-$600 setting up expense followed by the cost of livestock, building your own environment may be a more economical yet equally satisfying solution for you. One need not be apprehensive about constructing a mini-habitat. The following clues and tips are designed to make it fairly easy to establish and maintain a diverse and harmonious zooquarium.
A good starting place is a glass tank/aquarium. These can be purchased from biological supply houses (for $15) or local pet stores (for $7), or are often sitting empty in the garages and attics of students, parents and teachers in your school. The easiest size to find is a 10 gallon, but a 20 [gallon] long tank will house over twice as many species as a 10 gallon tank. It is also preferable to purchase a 20 long to a 20 high, because in amphibious exhibits, I find surface area to be more important than depth. An under-gravel filter and pump is essential as it uses a biological method to purify your water, and a wire or mesh cover is needed to prevent otherwise inevitable escapes. Under-gravel filters can be obtained inexpensively and an inexpensive alternative to the usually costly mesh covers is to fashion a close fitting lid from chicken wire--which is easily obtained and bent to size. Of course rocks of various sizes and gravel (preferably large and smooth) are necessary and should protrude out of the water in some areas to offer dry basking sights for amphibians. You should provide an external light source and your final abiotic requirement is aged or distilled water (tap water can be allowed to sit for 48 hours).
Autotrophs should be the first biotic residents of your zooquarium. Not only do they add aesthetic attributes but they provide hiding places, oxygen and food for many animals. Both terrestrial (i.e. Philadendron scandens, P. oxycardium and Pothos) and aquatic (i.e. water ferns, elodea) plants are recommended. Terrestrial plants should be pre-potted in water proof containers. They can be camouflaged by gravel and rocks but the top should remain above water level to prevent root rot. I have not had much personal success with rooted water plants such as elodea (also known as Anacharis), but floating plants like water ferns are successful in my zooquariums. Crushed coral is optional and has been reputed to counteract the ammonia from wastes maintaining the alkalinity of the water, however my zooquariums have survived without its use. Feeder guppies are the first heterotrophs in my zooquarium and are my favorite fish for a variety of reasons: they can be purchased a dollar a dozen, frequently bear live young (instead of eggs), don't produce as much poisonous ammonia as goldfish do, do not have demanding nutritional requirements and they work very well as part of the zooquarium food chain. Guppies are usually sexually dimorphic, the females being gray and typically larger and the males being spotted and having full colorful tails. Newts are a favorite among amphibians in my class. They resemble colorful lizards and are more aquatic (and smaller) than salamanders. The two varieties that I have most success with are the fire-bellied newts (darkly colored backs with red spots or splotches on their stomachs) and spotted or Eastern newts (may be green or orange with orange spots on their dorsal surface, and yellow with black spots on their ventral surface). Both newts achieve 3-4 inches as adults, not the 6-8 inches of Oregon newts (brown with orange bellies) and are thus not likely to other zooquarium inhabitants. Distinguishing between the sexes can be difficult, but males have thinner, broader more rudder-like tails than females. Newts will shimmy up filter tubing if given the opportunity, so a tightly closed lid is paramount to prevent escape and eventually desiccation.
Small frogs are also and exciting addition to a zooquarium, especially when obtained as tadpoles as your students can watch their development from tadpole to adult. Bullfrog tadpoles are plentiful in the spring and fall, however a full grown bullfrog can easily reach 8 inches and devour your entire zooquarium--as they can eat birds in the wild. Leopard frogs tend to remain smaller and are more colorful, but can also prove a peril to other zooquarium inhabitants. Water frogs tend to eat whatever is moving and can fit in their mouth, this extends to cannibalism as I discovered when I pulled a young bullfrog from my leopard frog's mouth. A few solutions to this potential hazard is to get frogs that are approximately the same size, remove frogs to separate containers as their size requires or get tree frogs--which seem to have milder temperaments and less voracious appetites. Green and Cuban tree frogs are varieties found most often in pet stores that do not seem to get too large. The suction pads on their toes may be easily observed since tree frogs prefer to perch in higher places, but you may end up with froggie footprints on the glass that can lead to more maintenance. Dwarf clawed frogs are excellence aquatic specimens that do not become very large. The albino variety is especially interesting for you can see many of the organs through its pale skin, however these frogs are usually pretty secretive. All frogs and toads secrete lubricants for their skin, some of which --as in fire bellied toads--can be toxic to other animals, so the variety of frogs in each zooquarium should be small. Similarly, students should always wash their hands before and after handling zooquarium specimens. As was mentioned earlier, frogs will only consume a moving target so they will need a diet of live insects. I recommend crickets, earthworms and meal worms (which can be kept in a dark plastic container with various kinds of meal and an occasional apple). Crickets should have their knees broken to prevent them from drowning and fouling the water. I have heard accounts of frogs eating cold-cut strips that have been dangled to simulate live movement. That's an experiment that I'm sure kids would enjoy to try.
Hermit crabs are fun arthropods, and can ideally (over many years) grow to the size of an adult fist. They require shells of increasing sizes to live in, as they do not form their own exoskeleton and will move to available shells as they grow. Many shells of assorted sizes and shapes should be accessible as hermit crabs can be finicky as they choose their homes. They are skilled climbers and seem to relish perching on a high branch or ledge of coral during the day while being most active at night. Hermit crabs need both dry and wet areas as they can drown if kept underwater for over an hour or dry out if kept without water for a few days. Fiddler crabs are also easily found in petstores and can be sexually distinguished by their large claw--which is only found in males. Similar to hermit crabs, fiddler crabs are scavengers that require both wet and dry areas. Be sure to get freshwater and not brackish hermit crabs if you want them to last for a while. Crayfish or crawdads are another type of crustacean that can be housed in your zooquarium, however I suggest very small ones, for although they are primarily scavengers, I have seen larger ones attack, fish, tadpoles and frogs.
Turtles, even small ones, are not recommended for your zooquarium, for they have the appetite of a Goliath bullfrog, produce about as much waste as a fertilizer factory and will overturn plants and rocks alike. If turtles are your passion I recommend a separate exhibit dedicated to their care. Freshwater mussels are very undemanding zooquarium occupants that prefer burying themselves in the zooquarium substrate. They filter food particles floating in the water, and are amazing to watch. I have not seen them often in pet stores, but they can be found in the sand of some lakes and large ponds. These are the only wild caught organisms in my ecosystem. Although it can become expensive purchasing a large number of animals, there are several practical advantages as well as ethical considerations to using captive bred over wild caught specimens. Captive bred organisms are more likely to be acclimated to captivity, and therefore they will have less stress and longer lives in your artificial environment. Using captive bred animals reduces the risk of exposing your zooquarium to various diseases and parasites. The captive bred animals mentioned above are easily and inexpensively obtained at less than $5 per animal and 10% educator discounts are available at most pet stores. Collecting and exhibiting native animals without proper permits is illegal in many states. Finally, captive bred animals don't reduce wild populations and they breed appreciation in your students for wildlife making students less likely to senselessly kill wildlife and more aware of actions that can harm-or protect-wildlife. Be informed that not every animal in a pet store is captive bred, and it is necessary to inquire where and how pet store animals are obtained. If however, purchasing animals from a pet store is still not comfortable for you, there are other alternatives. Contact your local zoo, for often they have a surplus list of animals that are either overbreeding in captivity, or that have been abandoned by owners that no longer want them. Also if you can find them, animal dealers that supply pet stores offer their animals at sometimes a quarter of the price as pet stores do, if you're willing to buy them wholesale.
Most of the organisms mentioned above can be maintained on commercial amphibian diets such as freeze dried tubifex worms, blood worms, brine shrimp etc. If you want to be extremely diligent you can find specialized food for salamanders, newts, guppies and hermit crabs. An occasional backyard insect will be greatly appreciated, but be careful not to collect insects that might be coated with pesticides. Your hermit crabs might appreciate fresh fruits and vegetables, but be careful to remove uneaten foods promptly. It is preferable to underfeed rather than overfeed your animals. Since these are ectothermic organisms with slower metabolisms, it is not necessary to feed them daily, two to three times a week should suffice. If food from a feeding is not eaten in ten minutes, then reduce the amounts of food given. Overfeeding will result in a muckier tank and may promote the growth of harmful molds and bacteria.
Water can be changed every two months or as needed in conjunction with an under-gravel filter. Many people will suggest changing a quarter of the water every month, but I have been successful doing a complete water change twice during the school year. Remember that only distilled or deionized water should be used, even when replacing evaporated water, because amphibians are very sensitive to chemicals and changes in their environment. Allowing tap water to age for 48 hours is sufficient.
Weekends and extended vacations are easily handled with a zooquarium. Since you have established a working ecosystem, a week without feeding should not disrupt your animals' lives. If you are still feeling wary about leaving them, you may use a weekend feeder available at pet stores with fish supplies, for your animals. If you do not have living plants to aerate the water, it is advisable that you plug your filter or aerator into an outlet that will not be accidentally turned of during the vacation. Over summer vacation you can be selfish and enjoy your aesthetic zooquarium in the comfort of your own home, or if you frequently visit your school or know a reliable custodian, allowing your organisms to stay in their classroom habitat relieves you of disassembling and reassembling your zooquarium. Following are some activities that are designed to integrate the zooquarium into your curriculum. They cross all academic and grade boundaries and can be tailored to suit the needs of your class(es). Enjoy your zooquarium as much as your students will.
Students can write a story or play about the experiences of an animal as it develops from an egg, to a tadpole to a frog, or the experience of a hermit crab as it tries to find a new shell.
Students can read or compose stories about their favorite animals.
Students can draw their favorite animal(s) camouflaged in its habitat.
Students can sequence events by ordering the stages of development of a tree frog:
*Back legs form (4) *Tail disappears (7) *Female frogs lays eggs on a leaf (1)*Tadpole drops into the water(3) *Eggs hatch into tadpoles(2) *Front legs appear(5) *Frog leaves water and goes to the trees(8) *Tail gets smaller (6)
Students can draw a food chain or web that exists in the zooquarium.
Students can find a picture of their favorite zooquarium animal in an encyclopedia and discover where it is found in the wild. Students can also draw a map of the country in which their animal is found.
Coborn, John. 1992. Proper Care of Amphibians. Neptune City, NJ: T.F.H. Publishing.
Hewitt, Jef. 1991. Keeping Unusual Animals as Pets. New York, NY: Sterling Publishing Company.
Kramer, David. 1989. Animals in the Classroom. Redding, MA: Addison-Wesley Publishing Company, Inc.
Mattison, Chris. 1993. Keeping and Breeding Amphibians. London [England]: Blandford; New York dist. in the U.s. by Sterling.
Orlans, F. Barbara. 1977. Animals Care from Protozoa to Small Mammals. Menlo Park, CA: Addison-Wesley,
