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Darters: Aquarium Designs And Care Guidelines
by Ray Katula
Darters are the second largest family of North American fishes and only
the minnows (Cyprinidae) have more species. With 150 known darter species,
their diversity of form and color are enough to keep many hobbyists and
biologists forever content.
However, darters are not for everyone. Almost all require a substantial
amount of live food in their diet and cooler water to maintain their color
and vigor. With the right conditions, they are fairly disease resistant, and
despite notions to the contrary, easy to propagate in the home aquarium.
This article will attempt to detail aquarium designs and care and
maintenance methods applicable to the darter tribe, Etheostomatini, in the
family Percidae (freshwater perches). The information presented here is
derived from over twenty years of the author's experience in collecting,
keeping, and spawning darters.
Before getting to the heart of this subject, I would like to highly
recommend two books to the darter researcher or aquarist: Handbook of Darters
by Dr. Lawrence M. Page and The American Darters by Robert A. Kuehne and
Roger W. Barbour. Both books are very good, and it's difficult to recommend
one over the other. Although the books note that natural history is lacking
for many species, all available information was consolidated at the time of
publication and the reader can often generalize within some of the subgenus
categories.
In order to better accommodate specific habitat needs of the various
darters, I will describe five aquarium designs. The 150 species naturally
inhabit nearly all the habitat types within their range. Lakes are perhaps
the least preferred habitat, however, tessellated darters (Etheostoma
olmstedi) are reported from lakes in the Northeast, Swamp Darters (Etheostoma
fusiforme) in the East, and Iowa Darters (Etheostoma exile) in the Midwest.
Based on my experience, swamps that host darters generally have some flowing
water from a nearby river or springs.
The habitat designs described below include: sand, pool, riffle, swamp,
and combination darter aquariums. Before dealing with specific strategies,
some general considerations need to be discussed:
- Darters frequent rocks which may encourage aquarists to construct large
rock piles. If this is done, glue the rocks together with silicone and keep
in mind to design caves with ample space. Otherwise, dead fish or debris can
become lodged and unknown to the aquarist. If silicone is not used, rock
slides are inevitable from the constant and sudden movements of the fish.
Ideally, it's better to scatter many single caves around the substrate where
entrapment of fish is less likely.
- Minnows can also be kept in the aquarium, but large numbers will
consume most of the food before reaching the bottom- dwelling darters.
Feeding minnows cheaper foods 15 minutes prior to feeding the darters helps
insure the latter are fed. Generally, small schools of minnows work best in
a mixed community aquarium.
- Larger sculpins and madtoms are tough, belligerent fishes which should
not be kept with darters.
- If filtration capacity allows, aggressive darters do best when slightly
crowded. Like African cichlids, one fish will not take over the whole
aquarium.
- Common aquarium plants are recommended, but native plants have seasonal
quirks and can be difficult to maintain year-round.
- Darters are very nervous fish which should have a full aquarium cover
to prevent jumping.
- Start with more common species and build on your experience. Many
darters are threatened or endangered and we don't want to put them in further
jeopardy.
- Often aquarium journals advise not to use rocks unless purchased at a
pet shop. There is always some risk rocks can leach toxic substances.
However, if rocks come from water inhabited by darters, they're probably
safe. Limestone is a good candidate which is usually very common and also
acts as a buffer preventing the pH of aquarium water from becoming
acidic.
- Two methods of filtration are recommended: powerheads and outside power
filters. On a long tank, it's best to position the outside power filter on
the side of the aquarium, which will maximize water flow. The author prefers
powerheads which are used to create a stream aquarium. However, there are a
couple of drawbacks. Powerheads slightly raise water temperatures and when
fully submerged generate the most heat. Aeration is highly recommended
either using the powerhead accessory or an air pump. This will counteract
low dissolved oxygen levels occurring in warmer water and also provides
surface agitation.
I. Sand Habitat
Species: All Ammocrypta spp. (sand darters) & glassy darters
(Etheostoma vitreum).
Setting up a sand bottomed aquarium and making it attractive requires
ingenuity on the part of the aquarist. A sand tank is not necessary to keep
sand darters, but is recommended to duplicate the species habitat for
observing and/or studying natural behaviors (e,g,. breeding). One
alternative the aquarist may opt for is sectioning off an area of a larger
aquarium and incorporating a sand substrate into a regular darter community
tank. This micro-habitat can be created using aquarium silicone to bond
rocks or pebbles into a shallow wall or barrier. This works well, but over
time the sand will become inundated with gravel. After flushing out the sand
darters, simply siphon out the old sand and gravel and replenish with clean
sand.
A whole sand tank will be easier to maintain, but various factors should
be taken into consideration. Undergravel filtration is virtually out of the
question. However, an outside power or canister filter will adequately keep
the water clean, but be sure the intake stems are well screened. Sand
darters are very skinny and can fit into some surprisingly small openings.
They also do not function as the best filtration medium. On small aquariums,
a sponge filter which is cleaned on a regular basis will suffice. Additional
aeration should be provided if there is little or no perceptible current
circulating through the aquarium.
Sand tends to compact itself. Uneaten food or other organic matter will
often (and quickly) turn the sand black which can create an anaerobic
bacterial bloom. One easy way to solve this dilemma is to add a small sucker
(catostomid) to the aquarium. The sucker's feeding activity will assure the
sand gets churned over and will effectively scavenge uneaten food.
Madtoms (Noturus spp.) are not always good tank mates because the skinny
sand darter can easily end up as food for a widemouthed ictalurid.
Valisneria plants located in the rear or side sections of the sand aquarium
will add subtle beauty to an otherwise dull tank. Sporadically placed rocks
should not hurt the sand darters, but are rare in the species natural
habitat. However, buried rocks would interfere with the substrate diving
habits of the sand darters. Once again, the casual keeper of sand darters
will usually find it unnecessary to maintain sand in the aquarium. The
author has successfully kept western sand darters (Ammocrypta clara) for over
a year in a gravel substrate aquarium.
II. Pool Habitat
Species: snubnose darter (subgenus Ulocentra), stippled darter
(Etheostoma punctulatum), and most Percina spp.
This is perhaps the most versatile of our proposed designs and should be
at least 20 gallons - larger is better. Aside from creating a pool effect,
the larger tank is necessary to accommodate the typically larger darter
species (e.g., stippled darters and Percina spp.). To facilitate keeping the
midwater darters as well as the bottom dwellers, smaller rocks and caves
should be landscaped in the front of the aquarium while leaving the upper
levels free of plants or rocks. Towards the rear, plants and/or rocks and
driftwood could be stacked to simulate a river bank. Currents should be
moderate but not strong. A bubble wand or other long airstone in the back
will provide additional and gentle aeration. In this type of set-up, it
might be best to aim the powerhead or outside filter outflow straight across
the width of the aquarium. This will hasten water movement, yet maintain a
gentle flow through the main portion of the tank. Some trial and error may
be necessary to accommodate each species preferences. Minnows work well in
this design, but numbers should be kept to a minimum which will assure
darters receive their fair share of food. A school of silversides
(Atherinidae) makes a nice addition to the upper levels of the aquarium.
Plants will often occur in natural pools and positioning aquatic plants to
the rear or sides will enhance the natural decor. Aquatic plants that do
well in the colder aquarium include, but are not limited to: Elodea,
Valisneria, Java Fern, Bacopa, and some varieties of Echinodorus (Amazon
sword plants). Because a pool tank can be relatively large, many
mini-habitats can be provided such as a sand habitat in one corner. A
careful positioning of the water outflow will also create conditions
favorable to riffle species as well.
III. Riffle Habitat
Species: Nothonotus darters: rainbow (Etheostoma caeruleum) and
orangethroat darters (E. spectabile), most Oligocephalus darters: saddled
(E. tetrazonum), greenside (E. blennioides), and banded (E. zonale) darters,
etc.
Most darter keepers will select this design because of the multitude of
darter species preferring riffles. A larger aquarium equipped with equally
large powerheads may be used, but for the riffle tank, smaller is generally
better. A 10-26 gallon aquarium is ideal, however, this author has used
plastic shoe boxes with modified equipment quite successfully. Depth is not
nearly as important as horizontal space. If used in a small tank, a
powerhead should be the type that emerges out of the water because
submersibles could warm water to lethal temperatures. In larger aquariums,
submersibles are rarely a problem because heat generated from the pump motor
is safely dissipated. With both powerheads and outside power filters, direct
the water outflow down the long dimension of the tank. The bottom should be
strewn with rocks forming caves. The more the better as long as rock piling
is limited. Very few aquatic plants can withstand the onslaught of
fast-moving water, but Cryptocorynes do well in the riffle tank if
temperatures do not drop below 60 degrees (F) for an extended period of time.
Fontinalis may grow well in the darter tank, but the author's limited
experience with this species has not met with great success. In this design,
the recommended minnows include Phoxinus (redbelly dace), Rhinichthys, and
Macrhybopsis chubs. Shale should be utilized when preparing an aquarium for
darters of the Catonotus subgenus (e.g., fantail and spottail darters).
Algae growth should be promoted when keeping darters that frequent riffles
with algae mats (e.g., greenside [Etheostoma blennioides] and banded darters
[E. zonale]). Many of the green darters will show enhanced coloration when
kept in a tank with lush algae. To provide such growth, good lighting will
be necessary. Choosing the right gravel substrate for any darter tank
requires forethought; too-dark or too-light will heavily influence darter's
color patterns and intensity. The commercial "natural" brands are best, but
personal taste will determine the choice (Note: natural gravels differ
regionally). In the riffle tank, use coarser grades of gravel which are
typical in these habitats. If undergravel filtration is used, the bottom
layer should be a standard grade of gravel and a larger grade and stones in
the top layer. The finer gravel will be necessary to provide an adequate
filter bed for nitrifying bacteria to thrive in. Additional aeration may be
optional if there is good water flow via the powerheads or outside power
filter outflows
IV. Swamp Habitat
Species: Iowa darter (Etheostoma exile), swamp darter (E. fusi- forme),
mud darter (E. asprigene), johnny darter (E. nigrum), and several other
Etheostoma spp.
The swamp tank will most resemble the typical tropical aquarium (minus the
heater). The tank need not be large and 5-30 gallons will suffice. Thick
plant growth and pieces of driftwood will constitute the primary decor.
Black gravel substrate works best to depict a mud bottom. Sand is
occasionally found in swamp habitats and could be introduced whole or as part
of the substrate (refer back to sand habitat section). An abundance of
rooted aquatic plants should utilize and absorb most waste products from the
sand. Undergravel or canister filters will provide sufficient filtration.
The force of outflow from an outside power filter or powerhead in most
situations would be too strong. Since this setup calls for slow moving
water, the choices of aquatic plants will be much more extensive than for the
other habitat designs. The one limiting factor might be their over wintering
tolerance. At room temperature, cabomba, myriophyllum, anacharis, dwarf
water lilies, cardamine, and many others do well. Some duckweed floating on
the surface can round out the natural plant elements of the aquarium. Rocks
are pretty much uncommon in swamps and as natural decoration should be
omitted or limited. If the use of rock is still desired, two types are
appropriate for the swamp tank: black shale rock can be situated to blend in
with the black gravel bottom. Petrified wood is better yet and often
imitates rotting wood. Driftwood often floats and may have to be weighted or
wired down. Recommended tank mates could include a small school of some
colorful southern minnow species, mudminnows, northern redbelly dace
(Phoxinus eos), or some mild-mannered native killifish.
V. The Combination Darter Aquarium.
This design combines elements of the first three strategies to accommodate
various species of diverse habitats. For obvious reasons, the swamp habitat
type cannot be incorporated. The combination of habitats will entail the use
of a larger aquarium and the standard 55 gallon is ideal. The positioning of
the water outflow over rocks scattered on the substrate yet allowing mild
flow through other portions of the aquarium will provide habitat conditions
favorable to both pool and riffle species. One optional alternative for this
design could include a sand corner addition for burrowing sand darters
(Ammocrypta ssp.).
Care and Maintenance
Overall, the same aquarium maintenance methods used on other native fishes
can be applied to the darter tank. However, water changes should be done
more frequently depending on temperature and filter effectiveness. If there
is undergravel filtration, stir the gravel during the water change. With the
present day use of chloramine and chlorine in many water systems, check with
the local water company to determine how to treat your water accordingly.
Chloramine is a very effective darter slayer. Airstones and diffusers should
be closely monitored because any loss in output could be disastrous under
crowded conditions. Filtration media should be changed regularly. Depending
on climate, the most difficult thing may be keeping the aquarium cool in
summer, and though not mandatory, over wintering in cooler temperature when
feasible will assure better spawning results in spring. Algae growth is not
detrimental and should be permitted wherever practical. The pH can vary, but
slightly alkaline water is the best bet if water from the collection site is
not available. Swamp species generally live in softer water at pH of
6.8-7.0. Rock salt at a tablespoon for every 5 gallons of water is a good
preventive measure for many common diseases. The two most important things
to remember are to keep the aquari- um cool and change the water often.
Copyright © 1991 - 2008 Ascot International
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