The Extremely Hardy Goldfish
The goldfish is the most common household pet in the world, and is kept both in aquariums and in ponds. It is a hardy, interesting, and lovable pet that can provide its caretakers with much enjoyment and affection. The goldfish, if cared for properly, can live up to 25 years. There are dozens of varieties of goldfish. These range from the common goldfish to a number of multicolored varieties. However, it is important to note that goldfish are classified into two groups for compatibility and other purposes.
The first group, generally called fancy goldfish, includes orandas and fantails. Fancy goldfish tend to have rounded, egg-shaped bodies and big, fan-like tails. They usually grow up to 4 to 5 inches long, but can grow bigger if given very good care and enough room. These fish will do fine in an aquarium. Use at least a 20-gallon tank with an external power filter and aerator. The ideal is to have at least 5 gallons of water per small goldfish. Fancy goldfish can be kept in ponds as well, but they should not be kept with the larger, faster, and more aggressive common goldfish, comet goldfish, and koi. These fish can be kept in water ranging from 45 to 80 degrees.
The second group includes common goldfish and comet goldfish. These fish tend to have long, slender bodies, and can grow over 12 inches long. These fish are excellent for the pond as they are very active, fast moving, extremely hardy, and can grow too big for an aquarium. They will get along great with koi. If you must use an aquarium and will have relatively large goldfish, make it at least 50 gallons for about four or five fish - that is about 10 gallons at least for each fish. For aeration and filtration, you can use an external power filter with built-in aerator. If you have a good-sized, healthy pond, natural methods may suffice in place of the mechanical methods. Get a good variety of water plants and a few scavengers like snails or catfish. This first group of goldfish can be kept in water ranging from 35 to 80 degrees.
Whether you keep your fish in an aquarium or a pond, remember not to overcrowd. For goldfish or any fish, the rule always holds: the bigger the container the better. Fish tanks are not at all expensive, and buying a nice, big tank is the best thing you can do for your fish. You should avoid keeping your fish in a goldfish bowl or other small container, no matter how hardy the fish is. As for food, feed your goldfish about once or twice a day. Take care not to overfeed - you can check this by making sure that most or all the food is finished within 5 to 10 minutes. Overfeeding is one of the main causes of dirty water and fish sickness.
Monthly (recommended for aquariums) or seasonal (recommended for outdoor ponds) water changes help a lot when it comes to keeping your aquarium or pond water clean, but a filter will make your job even easier. A filter works 24 hours a day and purifies the water in your tank by removing harmful chemicals and debris. Whether in an aquarium or a pond, live plants will also help provide essential aeration and oxygenation, as well as being a great hiding place and playground for the fish.
As mentioned earlier, goldfish can live in many different temperatures. Anywhere from about 40 degrees to 80 degrees is fine, and generally no heater is needed for any goldfish variety. Of course, most goldfish will feel most comfortable and have the least stress at a temperature of between 60 and 70 degrees. For pH, nearly all goldfish thrive at the 7.2 to 7.6 range, though a pH between 6 and 8 is also tolerable.
Goldfish are very hardy tropical freshwater fish that can tolerate cold temperatures well, and most can remain in the pond during the winter with proper preparation. The pond should be deep (at least 2 to 3 feet) and large enough, and care must be taken that the pond does not freeze completely. All in all, providing a stable pH and temperature range is usually more important than having an exact value, as long as extremes and sudden changes are avoided. For example, don't take fish from a home aquarium at 70 degrees and put them in an outdoor pond at 50 degrees.
Lastly, let us look at some of the major varieties of goldfish that you can get:
The Common Goldfish - This is the hardiest variety of all goldfish. It is most often a bright orange color, but occasionally may come in yellow, silver, brown, or a mix of these. It is an excellent choice for a pond, being one of the hardiest fish for weathering the winter outside. They can tolerate a temperature as low as 35 degrees, which is just above freezing!
Comet Goldfish/Comets - The comet is the most commonly owned goldfish, especially for the pond. A lot of people start out with comet goldfish, as these goldfish are almost as inexpensive and hardy as the common goldfish, while having a little more in terms of variety and coloration. Comets are usually longer and thinner than the common goldfish, and their tails are usually longer. These fish can live up to 25 years. They come in gold, orange, brown, red and white, calico, blue, orange and black, orange and white, and other combinations. The Calico colored comets are also referred to as Shubunkins.
Fantail Goldfish/Fantails - These goldfish come in many unique shapes and beautiful colors. An interesting variety is the Moor, which is all black and may have some gold coloration. The Moor's eyes also stick out on the sides - a very interesting characteristic. Ryukins are another variety of fantail goldfish that have a large chest and belly. Most fantail goldfish can live up to 25 years with good care.
Orandas - Orandas are most often orange or red, and may have some white as well. The oranda has a body shape and tail similar to the fantail, but it has a very distinguishing feature - when it reaches adulthood it grows a red or orange 'crest' or 'cap' on top of its head. The lionhead oranda typically grows an orange cap on its head, and a red cap oranda will have a red crest.