TEMPERATE WATER AQUARIUMS
These are not heated, and ideally the water temperature should vary to the same
extent that it does in nature (from 5 to 25°C, approximately). This is difficult,
as room temperature barely falls below 15°C and is often over 18°C. Apart from this
difference, the underlying principle is the same as in any aquarium: to recreate
an environment. This demands just as much time and care as with tropical aquariums.
It must be stressed that we are not talking about goldfish bowls!
Temperate aquariums house robust species, among them the fish found in our rivers
and ponds, which fall beyond the scope of this book. On the other hand, we will
cover goldfish (Carassius auratus), all too often neglected in favor of tropical
species, but which, in their innumerable variety, give great pleasure to many hobbyists.
Still within this temperature range, mention must be made of garden ponds, where
goldfish and koi carps (colored varieties of the common carp) can be kept and bred.
If they are well designed, such ponds can recreate a natural biotope, with aquatic
and terrestrial plants, invertebrates, and amphibians. Sometimes they can also play
host to tropical fish for a brief summer stay, if the temperature permits. After
all, fish can take vacations too, especially if they coincide with yours! It is
a practical solution when there is nobody to look after an aquarium during a long
absence, and when you come back you may be amazed by the weight the fish have put
on, or by some unexpected new arrivals.
On the other hand, do not be too surprised if some fish have disappeared, unable
to tolerate the change of setting - or the predatory instincts of the local cat.