Some Coldwater Fish

by Andy Gordon of England, and Michelle Stuart of Ontario Canada
Reprinted, with permission, from their web site Fishtanksandponds.net
Aquarticles

The following fish are suitable for a coldwater set-up. Some are readily available in shops whilst others can easily be caught in the wild. Such a set-up can be run on the same principles applied to their tropical counterparts but with two differences:
- Because the biological processes work more slowly at low temperatures the stocking level is half that of a similar sized tropical tank.
- And a careful eye must be kept on the temp., because as the temp. rises the oxygen level falls and this will really stress some of these fish.

The Chinese Hillstream Loach, Pseudogastromyzon myersi

Hill Stream Loach        photo by Andy Gordon

This fish is often sold under the name of coldwater plec. It is an extremely useful little fish because it eats massive amounts of algae.
They are entirely peaceful to the point where all other fish are completely ignored, so they can safely be kept with fancy goldfish. Their bodies are completely flattened and quite broad and they have a sucker mouth which they use to cling to stones in fast flowing water. They grow to about 3 in. These fish are occasionally sold from tropical fish tanks but they prefer cooler temps.
If there is no algae available for them they should be provided with some vegetable food. Although they will eat other food too. They seem to do better if a few are kept in the same tank even though they don't shoal. Through the day they prefer to hide, so provide them with some nooks and crannies.

Weather Loach
Grows to almost 12ins. so this is quite a big fish.
They are very good scavengers and will eat all manner of food. They live on the bottom of the aquarium all the time.
They get their name because they react to varying air pressure, The lower the pressure the more active they become. They even have been known to jump from the water, so keep them well covered. Their scavenging actively is so intense that they stir up the gravel and the water may cloud up unless you use an efficient filter. This makes them ideal in large goldfish tanks where an under-gravel filter is in use, because it prevents the gravel from becoming clogged up.
These fish can be a little boisterous but they are very peaceful. They are coldwater fish and should be kept in water no higher than 72 F. Their food consists of live, frozen, flake, or even vegetable matter. The heater must be guarded because these fish tend to want to hide in almost any tight nook or cranny, and they sometimes get badly burnt through trying to get behind the heater. If there are any plants in the tank they should be in pots or they will be dug up.

Three Spined Stickleback

Northern Redbelly Dace & Sticklebacks in the wild    
Photo by Michelle

The males in their breeding colours can rival any tropical fish for colour. But unfortunately they are also very aggressive so they must be kept in a species tank with just a single male. At first they will only accept live food but they will soon learn to eat the frozen equivalent, but it is unlikely that they will accept any form of dried food.
When breeding the male builds a nest like a small tunnel with two open ends, and he then displays to any passing female. If a female is ready to spawn she will enter the tunnel to lay her eggs, which are then guarded by the male. This process will be repeated, and so the males' brood will have lots of different mothers, none of which play any further roll in rearing the fry.
The maximum temp. that these fish remain comfortable in is the mid 70s but extra aeration should be provided when the temp is higher than 68F.

Northern Redbelly Dace
Northern Redbelly Dace can reach lengths of up to 5cm. They are generally found throughout North Eastern United States and Eastern Canada. They live in lakes, ponds, bogs, and slow moving water. They can handle temperature ranges from 50F to 75F with the 60's being their preferred range. They can live in a wide variety of pH from 6 up to 8. They are very intolerant of salts in their water and very sensitive to poor water quality. Redbelly Dace prefer a soft sandy or silty bottom substrate as they will dart for cover under the sand or silt when they are frightened.
These fish are mostly herbivores and will eat a lot of plant matter and algae. However they do appreciate insect eggs, larva and the occasional adult insect thrown in the tank for good measure!
During breeding, the male acquires a bright red underbelly (giving rise to their name) just before spawning in the spring or early summer. They are egg layers and will lay their eggs in a mass of algae, where they will be fertilized by the male. The fry hatch in about 7 to 10 days.

Rainbow Darter, Etheostoma caeruleum

Male Rainbow Darter                  Photo by Michelle

The Rainbow Darter is native to North America and they are members of the perch family. They can be found in small fast moving streams and small to medium sized rivers. They grow to be 2 to 3 inches in length with a natural life span of 2 to 3 years. They are a bottom living species that prefer a rocky substrate that is good for trapping food particles. In the tank they require good water quality which is slightly acidic (pH 6.5 -7). They can tolerate temperatures ranging from the low 50's up to the mid to high 60's. They eat mostly copepods, young crayfish, snails, insect larvae, and small insects. They will breed in temperatures above 60F. When breeding the female will only lay about 10 to 15 eggs at a time in a small protected area of the rocky substrate, and can lay over a 1000 eggs in a season. The fry will hatch in about 7 to 10 days.

Bullhead, Cottus gobio
This is a bottom living species with a wide flattened shape. It grows to between 4" - 6" and it is common across most of Europe except for the extreme north and south. It takes two years to fully mature and lives for about 5 to 7 years. The male takes care of the eggs and fry. It will eat anything small enough to fit in its mouth including the eggs, fry and even other adults if they are small enough.

Sunfish, Lepomis gibbosus
This is fish is found in lakes throughout most of Canada and the United States. They can adapt to a variety of water temperatures from 50F up to about 75F, however they do best in the 60's range. When fully mature they can reach a length of 6 to 7 inches. The water pH can range from 6.5 up to 8. They are very intolerant of salt in the water. They eat mostly insects such as dragonfly nymphs, snails, water bugs, worms or any other bug unfortunate enough to fall in the water when they are around. They will feed at both the surface and the bottom of the tank.
To get them to breed, they need to have a cooling period where the water temp. drops at least 10F for a month before bringing it up to regular temps. again. When breeding, the male will clean a spot in the substrate and encourage the female to lay her egg in the nest. The male will then protect the eggs by fanning them and rolling them around until they hatch.

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