The equipment you
will need for a brackish water tank is similar to a freshwater tank
but with a few additions. You will need:
Once you have all of
this equipment, you are ready to set up a brackish water tank. The question
now is: What fish should I get?
- Aquarium. Some articles claim that a 55 gallon or larger
aquarium is required for brackish water aquaria but this is untrue.
You could go as low as a 10g or even a 5.5g. The recommended set-ups
later in the article may help you chose tank size.
- Filter. The best filters for a brackish tank are hang on
the back mechanical and bio-wheel filters or canister filters. Undergravel
filters will not work properly with a sand substrate. For aquariums
larger than 20 gallons, you should use 2 filters on opposite sides
of the tank. You will want to have your water turned around 10 times
per hour (so you would need a single 300gph filter or two 150gph filters
for a 30g tank).
- Heater. Never go cheap on a heater. Submersible heaters
are much better at spreading heat and are less likely to shatter.
Make sure you get a heater marked for fresh AND saltwater use. You
also need to make sure the heater is adequate in size. A rule of thumb
is 5 watts of heat per gallon.
- Glass Top/Light Hood. All tanks should be covered and brackish
tanks are no exception. Keep in mind, also, that brackish water evaporates
faster than fresh water. If you plan on keeping plants, get atleast
1.5 Watts of light per gallon of water.
- Thermometer and Hydrometer. You will need the thermometer
to keep the temperature and a hydrometer to measure the salinity of
the water. A cheap swing handle hydrometer is fine for this situation.
- Substrate. Brackish water areas always are covered in a
sandy, silty, or muddy material and I feel that sand is the best option
for a brackish water aquarium. You could use marine aragonite, "Minerial
Mud", or play sand (which can be found VERY cheap at hardware and
home improvement stores). If you plan on keeping live rooted plants,
you will need about a 1" layer of substrate (avoid larger layers as
they can build up anaerobic spots) and for a fish only tank, a very
thin layer is best.
- Marine Salt. I prefer Instant Ocean but most brands should
work. AVOID Freshwater Aquarium Salt as this is not the proper salt
to use in brackish or marine tanks (although it is fine in full freshwater
tanks to fight off parasites).
- Water Condtioner. As with all aquariums, you will need a
product to remove chlorine and chloramine from your tap water before
placing it in the tank. Make sure the product is listed for both fresh
and saltwater use.
Brackish water fish
do not all come from the same brackish waters. Some are found in the
slow flowing estuaries and mangrove swamps while others are found in
the fast flowing saltier ends of rivers. Fish, as you would expect,
do better in as close to natural condtions as possible and therefore
I have split the brackish category into 3 setups.
Set-Up #1: Estuary
Estuaries are most
people's idea of where brackish water occurs. Estuaries are slow-moderate
flowing and the aeration from your filter(s) should be adequete. Although
there will be set-ups for smaller tanks down the line, an estuary tank
is best with a quite large aquarium.
Plants in this tank are very likely to be eaten. Java Fern and Java
Moss MAY survive. After raising your specific gravity over 1.015, these
plants will begin to die off and they should be replaced with marine
algae such as Caulerpa.
Sparesly decorate with rocks and branchy driftwood (that has been cured
to prevent leaks).
All of the fish listed above migrate down the estuary to the ocean when
they are several years old, so you will have to mimic this the best
of your ability. Buy all of your inhabitants young and start this tank
with around 2 tablespoons of marine salt per gallon of water. Every
6 months, add an additional tablespoon of salt per gallon of water during
water changes. Stop when you are adding about 7 tablespoons of salt
per gallon of water or when your hydrometer measures a reading of 1.020-1.025.
This should take about 3-4 years and they should not be rushed into
full marine water. Keep in mind NOT to add the salt directly to the
Set-Up #2: Brackish River
Towards the end of
the outward flowing rivers that empty into estuaries, there is brackish
water. These are fast flowing regions and you should attain an additional
powerhead directed to flow to the side to provide increased aeration
and movement. These set-ups are a great home to mollies, gobies, puffers,
and silversides and (in the case of Bumble Bee gobies) can be as little
as 5.5 gallons.
Brackish River Set-up:
Anubius, Vallisneria, Hairgrass, and Java Fern are best suited to the
currents of this tank although plastic is probably the best choice.
Decorate with taller plants in the background and shorter ones on the
side. Add one or more rock cave for your gobies. Anubius and Java Fern
should be attached to the rock cave(s).
Around 1-2 tablespoons of marine salt per gallon of water or a specific
gravity of 1.005-1.010 will be adequate for the full lives of most of
these fish. Green Spotted Puffers prefer saltier conditions with around
3-5 tablespoons of marine salt per gallon of water or a specific gravity
Set-Up #3: Mangrove Swamp
Mangrove swamps are
slow flowing waters covered in floating plants and mangrove roots. These
set-ups are designed to be part land, part water. For this reason, it
is recommended to use a 55g or larger aquarium so that there is enough
swimming room for the fish. The best filtration method in this case
would be a cannister filter with enough tubing to extend into the water.
Mangroves are the obvious choice for this tank. They should be planted
on the edge of the water and on the land section. As for aquatic plants,
since most are not readily available, plastic plants are best but you
could try Java Moss, Java Fern, Cryptocorne Bekketti, Hairgrass, and
The usage of tree root ornaments would be ideal in this setup. Many
mangroves and partially subdued lighting will make this tank more realistic.
These swamps usually also have floating plants covering the surface
but most of these plants are not available commercially (although you
could try java moss).
Around 3 tablespoons of marine salt per gallon of water or a specific
gravity of 1.010-1.015 will be adequate for the full lives of these
Once you have set-up
your tank to your desired brackish set-up and have fully cycled the
tank, you will have to learn a schedule of maintenance to care for your
I am a firm believer
of frequent water changes. I recommend cleaning 15% of your water once
a week. When adding the replacement water, make sure you add about the
same dosage of salt as before (unless you are running the estuary set-up,
in which case the dosage increases every 6 months). It is not necessary
to check with a hydrometer since these fish are naturally familiar to
varying levels of salinity but you should be within a good range of
accuracy to prevent shock.
One to two times a
week, you should stir up the sand with the back end of a fish net. After
stirring, turn the fish net to scoop the debris you have stirred up
into the net. If you are using 1" of sand or more, this stirring also
helps prevent anaerobic spots from forming (these spots can release
deadly gases into your tank).
Feeding should be
done atleast 2 times daily. All of the forementioned brackish set-ups
are recommended to have warm water (atleast 80F) and this increases
the fish's metabolism, causing them to eat more food and grow faster.
So, 2-3 feedings a day is much preferred, with 3 being optimal. Many
of these fish (mollies, monos, scats, knight gobies) require some vegetable
matter in their diet and puffers should be fed snails on occassion to
reduce the size of their "beak".
Once you have set up your brackish water aquarium and have
become accustomed to the required work, you will have created an entertaining
and low maintenance aquarium with some of nature's most unique and wonderous
Illustrations used in top banner courtesy of Popular
Freshwater Tropical Fish
The set ups and recommendations in this article are the opinions
of the author. Badman's always wants to provide the best information
available, so if you have a comment or an additional recommendation
please Email me and I will add them here.
Here there is
a recommendation of GSP's in a brackish set up. But what people
don't know, is that GSP's do not stay brackish. At 4-5" they need
to acclimate to full marine to live a full, healthy life. So you
have the GSP's mixed with Bumblebee Gobies. The gobies need to
stay brackish, therefor there is a confliction of water requirements
with these two species in the long run. Also, the max GSP's (full
grown) in a 55 gallon should be 2, and that's pushing it. Each
GSP requires at least 30 gallons for himself. The reason is not
only the bio-load but the aggression of the fish in small quarters.