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NFC: Darter setup..........
Darters: Aquarium Designs And Care Guidelines
Ray Katula - Genoa, WI
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.
Robert Rice
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