This area of
fishkeeping covers goldfish, fancy goldfish and some smaller fish like White
Cloud Mountain Minnows, some Danios, minnows and some catfish. Larger fish like
Koi are best kept in ponds.
Areas covered here
are
|
The coldwater habitat
| Tanks | Fish | Fancy Goldfish Problems | Ponds |
Coldwater refers to
fish whose normal habitat is in the temperature range of 50-75ºF. This is not
'cold' as such but it is certainly within the range of room temperature and
does not require the addition of a heater to the aquarium. Many of these fish,
including goldfish and Koi will survive quite happily outside and will even
over-winter in an outdoor pond.
The requirements of
coldwater fish are the same as tropicals, with the exception of heat. The water
needs to be chemically, biologically and mechanically clean, aerated and not
over stocked.
The differences
between cold and tropical tanks come about due to the changes in water
temperature.
Cooler water
contains more oxygen than warm water so it might seem that you could keep more
fish for a given size of tank. This isn't so though. The cooler water slows
down the fish's metabolism and the metabolism of the filter bacteria that are
so important in keeping your tank or pond healthy.
Fish digest their
food less efficiently so produce comparatively more waste and the bacteria that
process the waste work less efficiently, so you need proportionately more
filter/fish.
A tank for a
goldfish should ideally be a minimum of 5gals. with a filter. Remember,
goldfish can reach 10-12" when full grown. There are small undergravel
filters available for bowls but the small amount of water makes maintenance
more difficult and the conditions less stable. A basic tank with an air driven
under gravel filter is fine for goldfish. It is possible to set up a planted
goldfish tank but remember that goldfish are omnivores and will eat plants.
Some of the hardier varieties like Java Fern will survive but soft plants like
Elodea (pond weed) may well be destroyed. Plastic plants are a much better bet.
One or two small clumps of elodea can be added as 'snack food' for the fishes.
Elodea is cheap enough to replace on a regular basis. If the tank is planted
densely enough with a variety of plants then the plants may just grow fast
enough to survive occasional trimming by the fish.
There are a number
of fish you can keep in a coldwater set up. Goldfish come in a variety of
shapes and colours. Don't mix fancies with ordinary goldfish though. The fancy
fish (Moors, fantails, bubble eyes and celestials) are far less efficient
swimmers than the 'ordinary' fish (comets, shubunkins and plain old goldfish)
and will be stressed by their faster moving cousins. The longer fins and
protruding eyes may also be subject to nipping. Goldfish prefer moderately
alkali, hard water, pH about7.2-7.8
Similarly smaller
fish like white clouds and danios don't appreciate sharing their accommodation
with giants.
Some fancy goldfish
are prone to swim bladder and digestive problems. Because their bodies are
compressed their internal organs are squeezed. This can lead to fish floating
as the swim bladder is displaced or infected. Swim bladder problems have been
difficult to treat in the past but there are some more effective treatments now
available. See your local store for more information.
Another problem that
can lead to floating fish is trapped gas in the intestines. The fish
occasionally ingest air when feeding and this and other gases can become
trapped in the intestines. The difference between the two is that gas problems
occur intermittently, often after feeding, while swim bladder problems are
permanent. Digestive gas problems can be helped by feeding sinking food and
adding live or frozen bloodworm and daphnia to the diet.
Ponds, like
aquariums, come in a huge variety of shapes and sizes. A whole web-site could
be devoted to their design and construction so I will only cover some basic
information here.
At its most basic a pond
is a waterproof hole in the ground, full of water. Before adding fish, fit a
pump and filter. The better systems use gravity fed filters. These are fed by
drains in the base of the pool and the clean water is pumped from the filter
back into the pond. This system is ideal for large ponds and for ponds
containing Koi. Koi ponds should be large anyway, with a depth of at least 4
ft. Koi can grow to 3 ft. or more and need to be able to swim up and down as
well as round and round. The next best option is a solids handling pump that
removes wastes from the pond to the filter where they can be more easily dealt
with.
Planted ponds can be
built with shelves at various depths to accommodate the various plant types.
Marginal plants like reeds need a water depth of about 9" while
oxygenators and water lilies need about 2 ft. The plants are planted in slatted
baskets that help to contain the soil and make it easier to remove plants for
trimming and re-potting as they grow. Planted ponds and Koi don't mix; the fish
will dig up and eat any plants you try to introduce. This will foul the pond
and you won't see the fish for mud.
Other useful
features in ponds are a minimum depth of 2 ft. in part of the pond, to allow
the fish to over-winter successfully, and a sloping beach area or ramp to allow
amphibians, birds and other wildlife to drink and get in and out of the water.