Dr. Ted is a columnist at Tropical Fish Hobbyist
Magazine and the author of the new Animal Planet/TFH book, Aquarium
Care of Livebearing Fish.
in the Water Garden
by Dr. Ted Coletti
New Jersey USA, Zone 6
with photos by the author
Click to enlarge
I love my water gardens. Particularly the anticipation and
reward that comes from discovering that first flower from that
new waterlily. Winter here in the New Jersey Skylands is made
more tolerable with a pond catalog in hand, and a dream in an
armchair of what I will do outside when spring arrives.
But in my heart of hobbyist hearts, Im a fish guy. A
card-carrying member of the organized aquarium hobby. One of
those guys who keep dedicated rooms in their basements for breeding
fish and CO2-injecting plants, meets once a month in dark veteran
halls and nature centers to swap exotic fish, and enjoys rousing
discussions on do-it-yourself automatic water changing systems
and brine shrimp hatcheries. I enter fish shows and go to aquarium
Oh yeah, most of us dont care for goldfish or koi either.
So what am I doing here besides writing an article for WGIs
fine journal (after all, who can ever refuse Kit)? I keep tropical
fish outdoors in the summer. Thats what got me into water
gardening. And it is a practice overlooked by many pond
plant folks as a way to enhance your water gardening experience.
Keeping and breeding tropical fish outdoors in the warmer
months is a practice as old as the 100-year-old tropical fish
hobby itself. It was a quiet, quirky custom until about 10 years
ago when the pond craze cycled through here in the US, and folks
like me started rediscovering this lost art. Ive been personally
espousing the practice, which I coin summer tubbin,
in my writings and speaking engagements for a decade. It continues
to grow in popularity among aquarium hobbyists, and I think it
has brought more of them to appreciate the water garden.
Cold-hardy tropical fish, like Variatus
platies and rainbow goodeids, do
wonderfully in the water garden.
Just like aquatic plants grow, propagate, and develop better
outdoors in natural sunlight than in a home aquarium, so it is
with tropical fish. This is a key reason for the aquarium hobbyist
to take it outside in the summer. Raking up those
Breeder Award Points (BAP) for your local club was never easier!
The abundance of natural live foods and algae in an outdoor water
garden (including micro-organisms so critical for the raising
of fry), as well as the copious spawning sites among roots and
foliage, engenders an almost ideal environment.
The color that develops in tropical fish raised with such
varied foods and, as many of us believe, natural sunlight, can
rarely be matched in the home aquarium. Ye old fish guys of yore
used to purposely raise their show fish for fall competition
outdoors in the summer for this very reason. It has worked for
me on several occasions as a few trophies and plaques can attest.
All with less work than my fishroom buddies endure.
Tropical fish are ideal for the summer water garden, and better
suited in many ways than the stalwart goldfish, koi, and damnbusia
mosquito fish. To wit:
their small size makes them perfect for a variety of
sized water features
no need for aeration or mechanical filtration for small
to medium species.
little if any feeding is required
much smaller biomass results in less algae and water fouling
will not eat nor destroy our precious plants
greater variety of shapes, colors, finnage, and behavior
developing your own strain of fish
Before embarking on tropical fish in your water garden, I
want to share with you how I, a hardcore aquarium hobbyist turned
water gardener, have been doing this over the past 10 years with
lessons learned the hard way ...
One of the authors working summer fish
tubs, early in the season, explored by his
daughter who is petting an albino paradise
fish. Flowering is N. 'Marliacea Rosea'
Your first consideration is climate. While there are many
cool-water tropical fish that can enjoy even my autumn ponds
here in northwest New Jersey, we cannot treat tropicals as we
do goldfish, koi, or native American fish as year-round outdoor
denizens. I do not advocate letting them die off in your pond
over the winter. Even though their small size and biomass would
not do much ecological damage, if any, to your pond or even small
water feature, it is an unethical and cruel habit that I cannot
condone. Youll have to net them out.
Since I use tub ponds, this makes retrieving fish easier,
especially when I tear down in autumn. Surplus fish that I cannot
house inside are disposed of in a variety of ways: (1) monthly
fish club auction; (2) local pet shop; (3) given away to responsible
fish keepers, and (4) sold off on www.aquabid.com in the case
of much-desired species.
A common misconception of using tropical fish in your water
gardens is that they will get sick when the temperature drops
or that they cannot tolerate anything else than tropical
water temperatures. In my 10 years summer tubbin
I have never had a tropical fish contract Ich ((Ichthyophthirius
multifiliis, white spot disease) or get sick from nightly
or end-of-season temperature drops. The Ich parasite develops
in the gravel bed of aquariums, which are a moot feature of my
The mistake people make when using tropical fish in water
gardens is that they put them out too early. Some tropical fish
that have been accustomed to pet shop temps in the mid 70s-80s
F (21+-27+ C) may become stressed when placed in water below
70 F (21 C) degrees. However, once they are accustomed, they
handle temporary drops (overnight or day) to 60s or even
50 degree F (15+ or 10 C) water temperatures with no problem
(remember: water temperatures are warmer than air temperatures
at night). It is the extended or sudden temperature drops (like
with a water change or cold snap) that might cause problems.
However, many of the Central American livebearers and mountain
Asian barb species prosper well into the fall when daytime water
temperatures are in the 50s F (10+ C).
Those of you in the southern US zones will naturally have
a longer tropical fish and plant season than we do here in the
north. Regardless of where you live, my rule of thumb (learned
the hard way) is to put out your tropical fish when you put out
your tropical waterlilies (>70 degrees F [>21 C] water
temperatures). For me in Zone 6, that is usually Memorial Day
weekend or soon thereafter. Just watch your Weather Channel and
make sure the week ahead does not get colder. If the forecast
predicts cooler temps -- wait! (I know . . . this is difficult.)
I take in my regular tropical fish in September, but let my
cool-water species stay out through October. Again, watch the
weather forecasts and get them in before a long cold snap or
freeze comes. I lost several species a few years back in outdoor
aquariums when a multi-day frost came in mid-September (tubbed
fish did much better). You lucky ones in the southern zones can
enjoy another month or two.
Your next consideration is where to use tropical fish in
your water garden. My water gardening is strictly summer
tubbin. I employ a variety of receptacles ranging in size
from 5 to 70 gallons (19 to 265 liters) around my property. Tropical
fish are perfect for small water features, and will breed and
school in larger tubs (or ponds). This makes end-of-season retrieval
easier for me than those using large ponds.
At its simplest, the big box store 20 gallon (76 liter) round
plastic utility tubs sold for under $10 make for a great tub
pond. They come in a variety of seasonal colors to match to your
outdoor décor. If well planted, there are several species
that will flock breed in these, especially livebearers. These
containers have pluses and minus, however. They are deep enough
to hold in heat and provide cool zones for your fish. But their
taper towards the bottom makes it challenging fit a variety of
plants. They will also crack after about 10 years, or sooner
if not stored away from winter winds.
Better for about $20 are the pre-form barrel liner tubs, which
are also 20 gallons (76 liters) but have a wider bottom and are
more pliable. Either container can overheat, however, when placed
on concrete in full sun. This heat is great for breeding labyrinth
fish, but I have found it also leads to more stagnant conditions.
This effect is mitigated by placing the tubs on your deck, or
on slats where air circulation can occur.
Next up are the pre-formed ponds which are sadly not as readily
available in hardware and garden stores any longer. I use several
of the $35 34 gallon (129 liter) shallow round tubs, as they
contain 3 shelves for my marginal aquatics collection. This flexible
design along with their 36 inch (91 cm) diameter makes for good
flock breeding while creating a diverse plant arrangement. However,
they are also raccoon friendly! (More on this in another installment.)
As you know, there are many other sizes and shapes of pre-forms
that can be dug in or left free-standing.
Another option for me, which are especially helpful for larger
waterlilies, are the Rubbermaid structural foam stock tanks which
can be special ordered at your hardware store or purchased at
farm supply outlets. These are the only tub ponds I keep out
all winter without fear of cracking. At about $70 for a 70 gallon
(265 liter) (40L x 32W x 24H [102x81x61 cm]),
they are an investment that will last a lifetime. No shelves
(more next time on how I solve that problem) but great temperature
control under any setting and a handy drain at the bottom. There
are smaller and larger sizes available. See the Rubbermaid Commercial
website for details.
Of course, because of the small size of most tropical fish,
any container can work. I may utilize 5 gallon (19 liter) buckets
for raising fry or small fishes if there is some shade, as well
as large plastic containers if they are buttressed so as to avoid
bowing or cracking. Three gallon (11 liter) decorative flower
pots worked beautifully for guppies and micro-potted marginals
last year. Under my deck, I often setup an outdoor fishroom like
our Hawaiian aquarium hobbyists enjoy. If you go this route,
keep in mind that fish are more susceptible to freezing in such
tanks, and unless shaded, algae will cover the glass.
Where you position your tropical fish ponds is also a consideration.
Seasoned water gardeners know the sweet spots in
their garden where certain plants just do better than others,
and where less water problems seem to arise. The same goes for
tropical fish tubs and ponds -- especially smaller vessels. There
are so many variables in play from the substrate your pond is
placed upon, sun exposure, nearness to a wall, predators, etc.,
that I encourage you to experiment. A large deep pond or tub
will weather varied conditions much better than smaller receptacles.
< A variety of containers
What about filtration and aeration? Unless you plan
on keeping the larger tropical cichlids, catfish or barbs, I
eschew mechanical filtration and use natures vegetative
bounty for removing all the nitrogenous wastes these little fish
create. Oxygen is not a problem when lightly stocked, or if the
pond/tub is wide, thus providing ample surface area for gas exchange.
On a side note, why you pond folks still speak of oxygenators
makes us aquarium hobbyists chuckle. Surface area is the primary
determinant of oxygen content. Not amount of plants will overcome
a small surface area!
So Which Fish?
Theoretically, any of the thousands of aquarium-friendly freshwater
tropical fish can be used in the summer water garden (or spring
to fall for you in the deep south). The species I will be reviewing
are the ones I find most hardy, small in size (1-3
[2.5-7.5 cm]), available at retail (or via Aquabid), do
not hide from their owners, and are relatively easy to breed.
Temperatures listed are minimum maintenance water temps
to assist you with timing their removal from your pond as the
season winds down. Water temps in the 90s F (32+ C) during
the day are generally tolerated. A temporary cold day that warms
up again should also not effect them. As recommended above, the
real issue is acclimation from a warm retail store to the varying
temps outdoors. Put out your tropical fish when you put out your
tropical waterlilies (>70 F/21 C)!
Barbs, goldfish and koi fall in the same family of fishes
(Cyprinidae), and share many of same features (barbels,
shoaling behavior, fast swimmers). But the aquarium barbs are
generally much smaller. Some barbs can be fin nippers, and many
are good at eating thread algae. Their oxygen needs are somewhat
higher than other aquarium fishes, so a couple of pairs for a
24 (61 cm) diameter barrel pond would be maximum for the
below species. These species will tolerate and breed in a wide
hardness and pH range, but neutral or slightly acid/softer water
is their native chemistry. Females are usually more plump and
less colorful than males.
Rosy Barb (Puntius conchonius). Hails
from southeast Asia. Males are more colorful, so obtaining a
pair is relatively easy. Flock breeds for me in 36 (91
cm) tub ponds. Very active. Minimum maintenance temp 16C/60F.
Odessa Barb (Puntius padamya). Another
Asian beauty with beautiful red body band and yellow dorsal.
Flock breeds for me in 36 (91 cm) tub ponds. Minimum maintenance
Gold Barb (Puntius semifasciolatus).
This is the color morph of the green barb developed by Tom Shubert
of Camden, New Jersey USA, circa 1950s. The fry resemble
mini versions of their parents. Flock breeds for me in 36
(91 cm) tub ponds. Minimum maintenance temp 16C/60F.
White Cloud Mountain Minnow (Tanichthys albonubes).
This poor mans neon may now be extinct in its
native China, but is farmed for the commercial trade. A cool
water fish great for the small water feature or tub and will
flock breed. Minimum maintenance temp 5C/40 F.
Zebra & Leopard Danios (Danio rerio).
These speedy surface swimming egg scatterers are spawn eaters,
but are so easy to breed that removing the parents will almost
guarantee a brood. Minimum maintenance temp 18C/65F.
My personal favorite class of fish; livebearing occurs across
several families, but represent only 3% of bony fishes. This
highly evolved reproductive adaptation (vivipary) ranges from
fertilization of eggs within the females body cavity to
birth in 30 days (Poecilidae -- guppies, platies, swordtails,
variatus, mollies), to umbilical cord fed embryos (Goodeidae)
which take 60 days to birth. Poecilidae males have a stick-like
anal fin called a gonopodium, and females can store sperm
for monthly self-insemination for up to seven months.
Livebearer fry are born larger than egg layers/scatterers
and thus, have a better chance of surviving hungry parents. All
the fish below hail from Central America. In order to keep the
females from being harassed, try to keep an even sex ratio, or
better still, outnumber with females.
Platy (Xiphophorus hybrid). Gold and
blue varieties are the most hardy. A rainbow of color forms are
available. Great for a small tub or water feature. Minimum maintenance
(Xiphophorus variatus or hybrid). Longer bodied than platies,
the blue or yellow variatus are nearer to the true species and
can withstand low temps for extended periods and cold snaps.
Minimum maintenance temp 16C/60F.
(Xiphophorus hybrid). These fish are
jumpers and get longer-bodied (up to 5 inches [13 cm])
so a tub of at least 36 (91 cm) is recommended.
Males spar with each other. Minimum maintenance temp 20C/68F.
(Lebistes reticulatus). Ideal for the smallest of water
features, they are more likely to be seen in a water garden than
the above Xiphophorus as they are primarily top swimmers/feeders.
Fancy strains make a nice display with their large colorful tails.
Hailing from South America, guppies are not as cold tolerant
as their Central American cousins, contrary to popular belief.
Minimum maintenance temp 20C/68F.
xantusi/furcidens. This lively goodeid reaches 4
(10 cm) and requires at least 30 (76 cm) width of surface
area. Goodeids have evolved to rapidly changing temperatures
and day-night and seasonal swings in their Mexican highland habitats,
so they are some of the best tropical fish for a water garden
with extended cold snaps. Minimum maintenance temp 18C/64F. Another
goodeid with the same maintenance requirements is Ameca splendens
(pictured). They are hardier but less lively.
The Labyrinth Fish
Labyrinth fish are an ideal fish for small and shallow water
gardens in summer, since they do not take in oxygen from the
water. Rather they go to the surface for atmospheric air utilizing
a lung-like organ in their heads. This makes them easily noticed
in the water garden as they regularly come up to say "hello".
Many are tough charges too, enduring fouled water that would
weaken other fish. Males form a bubblenest for deposited eggs
and guard the nest.
Fighting Fish (Betta splendens). Unfairly kept in
small vessels, your betta will do much better and be happier
in your water garden. Only keep one male. Minimum maintenance
Paradise Fish (Macropodus opercularis).
A cool water tropical ideally suited for the water garden and
used by some lily growers year-round for mosquito control. Will
flock breed readily in a 20 gallon (76 liter) tub. The orangey
albino strain is nearly blind, and can be picked up in a cupped
hand of water. Minimum maintenance temp 10C/50F.
Blue/Gold/3-Spot Gourami (Trichogaster trichopterus).
Can reach over 5 inches (19 cm) in length, but aquarium specimens
are smaller. For breeding, adult size is required. Minimum maintenance
If you would like to deliberately breed aquarium hobby fish,
the water garden offers a perfect fishroom when water temperatures
reach around 80 F (27 C). The natural live foods in a pond or
tub range in size from the paramecium to the daphnia to mosquito
larvae, providing the protein needed conditioning the parents,
and for their fry to survive and grow. Lack of the proper sized
food and nutrition is the primary reason why many hobbyists find
it difficult to rear newly born egg-laying species.
Certain plants work better than others in my experience for depositing
spawn and creating refuse and grazing areas for fry. Established
thick-rooted marginals like Iris pseudacorus, Pontederia,
Typha, and Hibiscus should be employed in perforated
plastic pots. Floating water hyacinth is another great plant.
All these species are the work horses of the natural
vegetative filtration I use in all my water gardens. They are
my filters, spawning mops, fry protectors, anti-algae nutrient
sponges, and micro-organism salad bars. Water hyacinth (Eichhornia
crassipes) is the best of the bunch as it also helps to shade
and insulate a tub pond. Because many pond plants (and ponds)
carry hydra, which can devour fry, I like to disinfect my newly
acquired plants in a 24-hour dip of Fluke-Tab. This is especially
true of water hyacinth.
Be warned: moving your plants around you will probably hear
yourself at the end of season as you tear down saying now
how did this fish get over here?
Some egg layers devour their eggs, and thus require separating
the parents from their eggs after spawning. I employ the two
tub method here, where I will condition males and females
separately for a week or two with live and frozen foods like
mosquito larvae, blackworms, and baby brine shrimp. In the evening,
when dark, I will introduce the flock into one of the tubs. They
should spawn in the morning. I then remove them at dusk to the
other tub (if I want to ensure a spawn I will remove these pairs
as well after 24 hours to a different holding facility).
The authors son exploring his
dads breeding two-tub setup
Fry should hatch in summer in about 24 hours, but will be
too small to see. Commericial liquid fry food, green water, and/or
frozen rotifers are good first foods to supplement their natural
water garden diet. After a week you should be able to tell with
a fine mesh dip net (e.g. brine shrimp net) whether your efforts
were successful. Now you can start offering small foods like
live or frozen baby brine shrimp, daphnia, and powdered flake
I hope this introduction to tropical fish in the water garden
inspires my fellow members to take the plunge. Who knows? You
may find yourself building a fishroom or rack when the season
is over as you develop yet another hobby. Warn the wife.