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University of Kentucky Department of Entomology - KENTUCKY BUG CONNECTION
Youth Entomology Resources | MIDDLE - HIGH SCHOOL


PET BUGS: Kentucky Aquatic Insects
How to acquire and care for aquatic Kentucky arthropods.

Giant Water BugHome aquariums are usually reserved for fish, but they also make great habitats for freshwater aquatic insects.  Dragonfly naiads, diving beetles, and giant water bugs are all common in Kentucky streams and ponds and can thrive in a properly maintained aquarium.  When several kinds of aquatic insects are kept in an aquarium along with fish, plants, and other organisms, an entire miniature ecosystem can be observed.  Listed below are some of the things that are needed to establish an aquatic insect habitat, along with some common wild aquatic insects that will thrive in a properly-maintained home aquarium.

Aquarium: Aquatic insects will need a ten-gallon or larger aquarium.  A filtration system is not needed, but air should be pumped into the tank.  The tank should be well-covered with a fine-mesh screen top because many aquatic insects can fly or crawl out of an uncovered aquarium.  Fill the tank only about 1/2 - 3/4 full -- the insects will be less likely to escape when the water level is low.  Line the bottom of the aquarium with rocks or gravel purchased from a pet store.  Rocks from local streams and creeks can also be used, but can sometimes cause a chemical imbalance in the water, so it is usually best to use pet store rocks.

 Water: The most important thing about any home aquarium is the quality of the water.  Chemicals that are present in tap water and that are generated by aquarium organisms can kill even the hardiest of creatures.  One of the easiest ways to minimize these effects is by allowing aquarium water to "age."  To "age" aquarium water, fill your aquarium with tap water to a few inches above the desired level, turn on your air pump or filtration system, and allow the water to sit for at least a few days.  This will allow most of the tap water chemicals to evaporate.  In the meantime, keep a separate bucket filled with tap water The water in the bucket will age without a filtration system or air pump, but more slowly.  As the water in your aquarium evaporates, refill with small amounts from the bucket to the desired level.  After the aquarium has aged for a few days, add 2-3 hearty freshwater fish (such as mosquito fish or goldfish) to the tank.  Maintain the fish for an additional week or so -- as the fish eat and produce toxic waste chemicals, microorganisms will gradually build up in the aquarium and consume the waste chemicals.  Once green algae begins to grow in the aquarium, it is usually a good sign that it is safe to add aquatic insects and other organisms.  We don't have enough space here to go into all the details of maintaining healthy aquarium water -- and we are not aquarium experts! -- so it is best to seek advice for your freshwater aquarium from a pet store.  Note: it is best NOT to use water from lakes, ponds, and streams.  It is difficult to transport and may contain disease organisms that will kill your aquarium inhabitants.

Plants: Aquatic insects thrive best when aquatic plants are also growing in the aquarium.  Plants provide a place for insects to crawl and hide, and can even be a food source for some insects.  Ask your local pet store for recommended freshwater aquatic plants.

A Word About Mosquito Fish: Mosquito fish are a great resource for those of us who love to keep freshwater insects.  Mosquito Fish (also called "Gambusia," from their genus name) are very common in Kentucky streams and ponds, where they eat mosquito larvae and other small creatures.  They are a very hearty fish, and can be used to condition aquarium water (see above).  They are also a perfect food source for predatory aquatic insects.  Immature mosquito fish, in particular, are a great, easy to capture food source for many aquatic insects.  Many aquatic-insect enthusiasts raise mosquito fish in a separate aquarium (such as a small, 2.5 or 5 gallon tank) to guarantee a constant food source for their insect predators.

Temperature: It is best to keep your aquarium at temperatures between 60 - 72 degrees F.  Do not place the aquarium close to a window: direct sunlit can quickly heat the water to temperatures that are deadly for aquatic organisms.


PREDATORS: Predatory insects are generally the easiest to find and the easiest to take care of in an aquarium.  Examples include: dragonfly and damselfly naiads, predacious water beetles, giant water bugs, and water scorpions. All of these insects can be fed with small minnows captured in local creeks and ponds, or with small feeder fish (such as guppies) purchased from a pet store.  For a continuous food supply, breed guppies or other small fish (such as mosquito fish) in a separate aquarium, as mentioned above.  Predatory insects will often feed on other creatures in your aquarium, including each other.  To reduce this problem, keep only a few predatory insects in the aquarium and provide them with plenty of feeder fish.  Also, hiding places like rocks and aquatic plants help reduce aquarium casualties.


Damselfly Naiad
Damselfly Naiad
(B. Newton 2003)

Dragonfly Naiad
Dragonfly Naiad
(B. Newton 2004)
Giant Water Bug
Giant Water Bug
(B. Newton 2002)

Visit our Case Files: Giant Water Bugs, Dragonflies, and Damselflies for more information about these insects, including where to find them and how to identify them.

Adult Dragonflies and Damselflies: Note that dragonfly and damselfly naiads are only aquatic for a part of their lifecycle: after a few days or months (depending on their age when they are caught), these insects will shed their skins and become flying adults.  Adult dragonflies and damselflies cannot be maintained in captivity, so it is best to release these insects near the same water source where they were captured as soon as they emerge.

Water Scavenger BeetleHERBIVORES AND SCAVENGERS: Although not as commonly kept as predatory aquatic insects, there are several herbivores and scavengers that will thrive in captivity.  Water scavenger beetles (pictured on the left) and crawling water beetles are both common in Kentucky ponds and streams.  They will feed on aquatic aquarium plants and they will also help keep the aquarium clean by eating waste and dead organisms.  They will also feed on fish food.

OTHER CREATURES:  There are a few non-insects that are often found in Kentucky aquatic habitats that will thrive in captivity.  Crayfish, in particular, are easy to find and will live for years in a healthy aquarium.  They will feed on fish food, especially the large pellets designed for bottom-feeding fish.  Beware that crayfish will tend to dominate an aquarium by killing and eating the other bottom-dwelling inhabitants.  

Not recommended: There are several aquatic insects commonly found in Kentucky streams which do not thrive in a typical freshwater aquarium.  Mayfly and Stonefly naiads, in particular, are very common, but usually need to live in fast-moving water.  They are good prey items for predatory aquatic insects, though.


Kentucky Bug ConnectionYouth Entomology Resources | PRESCHOOL - ELEMENTARY
For preschool and elementary educational materials, please visit our adjacent site, KATERPILLARS.

Photos courtesy B. Newton and R. Bessin, University of Kentucky Department of Entomology.

Original document: 19 April 2004
Last updated: 19 Oct 2006

This page is maintained by Blake Newton, Department of Entomology, University of Kentucky.
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