Page 314 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

312 POND FISH: SETTING UP THE POND

Coldwater fish in the home

Many coldwater fish can be kept indoors in aquariums;
indeed, some of the smaller, less colorful species are SETTING UP A COLDWATER AQUARIUM
more visible there than in a pond. Even larger species, The setup of a coldwater tank is very similar to that of a freshwater
such as koi and sterlets, may be housed in a tank when tank (see pp.38–42), except that it lacks a heater and can support a
different range of plant species. Coldwater tanks benefit from a
small, but they must be moved outdoors when they simple filtration system, such as an undergravel or power filter
(see pp.34–35). Lighting is important; a light in the hood assists plant
outgrow their surroundings. Some coldwater fish cannot growth and enhances the visual impact of the fish. Pale-colored
survive the winter in a pond, especially in temperate gravel is the best choice for a goldfish tank, providing a striking
contrast to the fish’s vivid colors; avoid red or blue gravel, because
areas, and must be housed indoors until spring. it makes their coloration appear dull. Goldfish excavate the gravel
when searching for food, which can make it difficult to establish
plants. Protect the plants by securing them in place with rocks.
It is no coincidence that, numerically, goldfish (see pp.332–343)
rank as the most popular pets in the world. Their care,
whether indoors in aquarium surroundings or outdoors in a
pond, is very straightforward. Not only are goldfish unfussy in
their water chemistry requirements, but they will also live
happily in unheated, dechlorinated tap water. Goldfish are
generally not nervous or shy, especially once established in
an aquarium, and it is usually possible to keep two or more
together without difficulty. Different varieties can successfully
be kept together in a single tank, but it is best to avoid mixing
fancy varieties with goldfish with simple fins and tails; these
attractive fish were bred for their looks rather than their

swimming ability and may lose out to their more agile
relatives in the daily competition to find food.
Although less commonly kept, small minnows and other
similar-sized coldwater species will also thrive in planted
aquariums indoors. Others, however, notably members of the
sturgeon family, may not thrive at typical room temperature,
especially when young; this is because they stop feeding at
water temperatures of more than 68°F (20°C).
Seasonal accommodation
Some species of coldwater fish that are kept in a pond over the
summer months must be moved indoors for the duration of
the winter. This particularly applies to fancy goldfish varieties,
which are not hardy enough to overwinter in cold, possibly
freezing, water. Their corpulent body shape means that
they are especially vulnerable to swim bladder problems
linked with low water temperatures, which cause them
to float at an abnormal angle in the water. Set up an
aquarium in advance of the start of colder weather,

Shubunkins and other goldfish root around in the
aquarium substrate, sucking in and spitting out pieces
of gravel in their search for edible items.

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