There are basically three types or divisions of
tropical fish, freshwater, saltwater and brackish. If we
are speaking of freshwater fish, only, then there are only two
types, we need concern ourselves with, livebearers an egg
layers. This page is devoted to brackish water fish.
Because of the expertise needed and special requirements of this
category of fish, they are not recommended for the beginner
aquarists.
Brackish fish originate from areas in which freshwater meets
saltwater. Fish that live in these areas are able to tolerate a
wide range of salinities. Brackish fish do best in water with a
salinity of 1.015, or one to two teaspoons of salt per gallon,
and a pH of 7.5 or higher.
Half freshwater and half marine, brackish aquariums are home to
some of the more stunning and unique fish in the hobby. This
special niche is growing rapidly thanks to a better
understanding of the brackish biotope and advancements in the
equipment needed to provide the proper conditions. Despite their
mystique, brackish aquariums are fairly easy to maintain since
brackish inhabitants are conditioned to the moderate
fluctuations in water parameters due to the normal tidal cycles.
Brackish habitats can be found in nature throughout the world
where river deltas meet the ocean
estuaries, mangrove forests,
or swamps. In a brackish habitat, salinity varies depending on
the tide, the amount of freshwater entering from rivers or as
rain, and the rate of evaporation. Water clarity can range from
totally clear to murky. Water conditions range from 70-86°F,
with a pH of 7.2-8.3, and a specific gravity ranging from
1.006-1.015.
Not all species of fish can adjust to ever-changing brackish
conditions. Those fish that do are hardy, active, and easy to
feed, making them a good choice for most enthusiasts. Setting up
and maintaining a brackish aquarium for these fish is not
difficult. In fact, a brackish set up is basically a freshwater
aquarium that requires the addition of sea salt and ongoing
testing to maintain specific gravity in a suitable range.
A few of the most popular brackish water species are:
Archer Fish
Distinctive, triangular silver body; has the remarkable
ability to spit water at insects above the water.
Black Sailfin
Molly This species should only share
a tank with other peaceful fish. Also known as Mexican Sailfin
Molly, Giant Sailfin, and Yucatan Molly.
Figure 8
Puffer Unique coloration, appearance,
and personality; when threatened can inflate to twice its normal
size.
Green Scat
Gradual change from brackish to saltwater will maximize the
beautiful coloration of this fish as it matures.
Mono Argentus
Diamond-shaped, silver in color, with two black stripes on the
front half of its body; grows very large.
Below are some pictures of some of the more popular Brackish
Water fish.
Brackish habitats can be found in nature throughout the world where
river deltas meet the ocean. These environments are known as
estuaries, mangrove forests or swamps.
The brackish aquarium
is home to many popular fish in the hobby such as the dog faced
puffer, monos, scats, shark catfish, mollies, gobies, spiny eels
and killifish to name a few.
The set up for this type of aquarium is not different to the common
saltwater tank. The conditions generally found are temperatures
from 75-82 F (24-28 C) with a pH of 7.2 8.0 and a salinity
between 1.006 1.015. Adjustments have to be made depending on
the species to be kept. The gravel should consist of coral sand
and driftwood. A moderate to strong current should be provided
by the filter system.
The Archerfish has excellent eyes and spends most of the time
swimming near the water surface. Feeding takes place by locating
insects sitting on plant leaves or are simply flying by. With
its mouth the Archerfish builds a tube and with a sudden closure
of the gills, the fish is able to shoot a stream of water up to
5 feet. The stream hits the insect with incredible accuracy and
throws it onto the water surface. The Archerfish is easy to
maintain, but also relies on live food as the only food source.
Another very interesting species is the Four-Eyed Fish. Other than
suggested by the name, this fish actually has two eyes, but
horizontally divided by a line of cells. The upper part is used
above the surface to look out for predators and the lower part
is used to find prey below the surface, resulting in 4 different
optical views at the same time. These schooling fish mostly
hover at the water surface and only dive down to feed. The food
source should also be live food such as crustaceans and worms.
All three of the above mentioned fish can successfully share an
aquarium, provided it is large enough, requiring 75 Gallons and
up. A brackish aquarium can be a beautiful and rewarding set up
where the imagination can run wild.
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