Today we are going to talk of one of the pioneer species in the world of fish tanks. It is the goldfish. Its scientific name is Carassius auratus and it is also known by the common name of golden carp. And it is that this species was one of the first to be used as pets after capturing them. Such has been their fame as a pet, that today they are the most abundant in the common fish tanks of all homes.
We explain everything to you Learn more about this species here. From its main characteristics to the care it requires to keep it healthy in our aquarium. Want to learn more about the goldfish?
Key features
This species of fish It often reaches between 15 and 30 cm in length in well-maintained aquariums and ponds, and specimens exceeding 35 cm have been documented in exceptional conditions. The wide variety of selected strains in China over the centuries explains its diversity of sizes, shapes and colors.
In the wild or feral state, robust specimens can increase in size, but It is not a fish weighing tens of kilosIn captivity, the usual weight is moderate and depends on genetics, water quality, and diet. Longevity is notable: with good care can live between 10 and 15 years or more, especially in large ponds with stable water, making them long-lasting pets.
In its natural morphology, the goldfish has rather elongated body and relatively small fins in relation to its size. Biologically it is similar to the carp, but is distinguished by the absence of chins at the top of the mouth. In ornamental varieties (oranda, veiltail, ranchu, etc.) the body can be more rounded and more developed fins.
The typical color is golden yellow or orange, although there are shades of red, white, black or combinations. The characteristic metallic shine comes from the guanine, a substance that reflects light through semi-transparent scales. They are agile fish with good swimming ability, especially the common varieties (common, kite fish, shubunkin).
In addition to being resistant, they are sociable and peaceful fish, suitable for living with other coldwater fish of similar size and needs. Due to their color, resistance, and behavior, they are perfect pond fish when offered a sufficient volume and well-filtered water.
Goldfish habitat
This fish has its habitat in all areas of sweet water. It is impossible to find it in the ocean. The most advisable way to prepare a habitat that is closest to nature at home is the use of ponds. These ponds guarantee greater mobility and an area where they are used to being.
In nature they usually live in small groups at mid-depth or near the bottom, where they look for their food. They frequent eutrophic environments (rich in nutrients and algae) and can tolerate waters with poor oxygenation. Some specimens have been observed to survive temporarily in waters slightly brackish, although its optimal maintenance is in fresh water.
In Europe and other regions, many feral individuals come from aquarium releases, something that should never be done because it alters ecosystems. Because of their striking color, they are found in nature easy prey from predators such as pike or perch and only thrive in isolated corners without intense predation.
Like carp, when feeding by stirring the bottom, they can increase the turbidity of the water, affecting the growth of aquatic plants and reducing oxygenation. Therefore, if they are kept in ponds, it is advisable control densities, provide adequate filtration and sufficient vegetation to mitigate its effect on the environment.
There are experts who have studied this species in depth and can affirm that They live better in captivity than in their own natural habitat when provided with a large, stable, and well-filtered aquarium or pond. A key factor in their well-being is the water temperatureIn cold ponds, their metabolism slows and they enter a state of rest, while in temperate waters they maintain constant activity.
Behavior and feeding
The goldfish has a fairly calm condition. They don't usually cause problems if they live with other species. Since they always stay together when there is more than one individual, it's rare to see one alone. In their natural habitat, they're more prone to fight with other species, but in captivity, they're truly calm. They're curious, explore their surroundings, and learn feeding routines. In fact, can recognize their caregiver and accept food from the hand with patience and reinforcement.
They are fish that tend to look for food in the substrate; therefore, it is advisable to use sand or gravel with soft edges to avoid injuries. A moderate flow of water benefits them, although They do not tolerate strong currents continuously.
As for their diet, They are omnivorousThey feed on plants, algae, and small invertebrates. Their natural menu includes insects, larvae, crustaceans, plankton and eggs from other species if they have the opportunity. This trait explains why they can prey on other eggs in community aquariums during breeding seasons.
To feed it if we have it as a pet, we don't have to worry. You can give him food sold in stores de peces whether you are alive or not. Supplement your diet with some live food might be a good idea. Some larvae, sea fleas, or bacteria are good options. For the plant part, You can give him lettuce and cauliflowerThey also accept spinach, peeled peas, and blanched zucchini. If you want to give them a treat from time to time, you can give them some shrimp, brine shrimp, or daphnia.
They are very gluttonous, so it is advisable do not overfeed them. Offer small portions 2-3 times a day, of what they can eat in a few 2 minutes. To avoid buoyancy problems, soak flakes or pellets so they sink, as swallowing air at the surface can affect their swim bladder. At first, if we haven't been with these fish for a long time, they'll be a little more fearful and reluctant to try food, but over time they'll get used to it.
Their predatory appearance can also be detrimental to their health in captivity. Capturing the eggs of other species can also happen in your aquarium or pond. These fish need to be more closely monitored when other species are in the tank. breeding season. Also, don't mix them with very small fry because they might mistake them for food.
Reproduction
This fish It is somewhat more complicated when it comes to reproducing. Conditions must be ideal for reproduction to take place. This occurs in both natural and artificial habitats. Sexual maturity is generally reached between the first and second year, depending on growth, diet and water stability.
Reproduction is not very complicated if the best care is taken from the very beginning The fish. If they're kept in ponds, reproduction is much easier. Ambient temperatures are more likely to induce reproduction when they're higher. What's important is for the water temperature to rise gradually, as is typical in spring.
Courtship is similar whether they are in natural habitat or in ponds. The most normal thing is that it is the male who chases the female to stimulate her. Fertilization occurs when the male pushes the female against plants, rocks, or spawning mops. eggs are adhesive and are fixed to vegetation or decorations.
It is an oviparous fish prolific: The female lays hundreds of eggs per batch. After fertilization, it is advisable remove the adults or move the plants with eggs to another tank to prevent them from being eaten. Hatching usually occurs at 48-72 horas, depending on the temperature. The fry begin attached to surfaces and, upon absorbing their yolk sac, begin feeding on infusoria and micronutrients.
Aquarium and maintenance
To recreate the optimal conditions In terms of your goldfish's habitat at home, it is essential to provide space, filtration, and stable water. Although they are often associated with small fish tanks, should not be kept in containers without a filter not even in crystal balls: they limit oxygenation, accumulate toxins and drastically reduce their life expectancy.
Tank volume and shape: For common varieties (common, comet, shubunkin) consider a few 75 liters per fish as a starting point; for rounded body varieties (Oranda, Ryukin, Telescope, Ranchu), at least 38-50 liters per fishA horizontal aquarium offers a better surface area for gas exchange and swimming space than a tall one.
Filtration and oxygenation: Goldfish generate a lot of waste. Use a oversized filter (waterfall or external) and add aeration if the temperature is high. Perform partial water changes of the 20-30% weekly and conditions the water to remove chlorine and chloramines. Some caregivers add a tablespoon of iodine-free sea salt per 19 liters as occasional osmotic support, avoiding continuous use and checking plant/companion tolerance.
Water parameters: Flexible pH between 6 and 8,5 (ideal close to 7-7,5) and general hardness 10-30°dGH. Recommended temperature between 18 and 24 ° C, with a sweet spot around 20-23 ° C for many varieties. Avoid sudden changes in temperature and water chemistry.
Substrate and decoration: uses fine sand or soft gravel without sharp edges; avoid abrasive rocks (lava, tufa) and sharp pieces that could damage fins or eyes, especially in telescope varieties or celestial eyes. Add hardy plants (Java fern, anubias, some cryptocoryne), knowing that they may nibble on them. Keep dim lighting and a moderate water flow, without excessive currents.
Compatibility and coexistence
The goldfish is peaceful and gets along well with fish of similar size and requirements. They are gregarious, so They appreciate living in a group, as long as the volume allows it. Avoid companions who peck fins or are very restless.
Do not mix them with tropical fish warm waters nor with extremely slow species if you keep common active varieties (comets or shubunkin), as they can take away their food. With very small fry there is a risk of predation. In outdoor ponds, protect goldfish from predators (birds, mammals, hunting fish) and offers plant refuges.
Health and disease prevention
With a good aquarium and quality water, the goldfish It has great resistance. However, there are common pathologies that should be prevented with hygiene and quarantine of new fish:
- White spot (Ich): small white spots, scratching, and lethargy. Responds to antiparasitic treatments and thermal stability.
- Dropsy: swelling and raised scales. It usually indicates bacterial infection/organ failure; requires prompt attention and water improvement.
- Fin rot: Frayed edges caused by bacteria/fungi. Prevented with clean water and is treated with antibacterials.
- Swim bladder: Abnormal buoyancy. Reduces floating dry food, soak the food and provides a varied diet with vegetables.
- Anchor worm and fungi: parasites and mycoses that enter with new fish/objects. Apply quarantine and specific treatments.
- Poor water stress: reddish veins in fins, panting at surface. Control ammonium/nitrites/nitrates with tests and water changes.
Watch for warning signs such as loss of appetite, lethargy, color changes, or erratic swimming. Early intervention and a protocol of constant maintenance They are the best medicine.
Popular goldfish varieties
All varieties belong to the same species, Carassius auratus, the result of centuries of selection. Among the most common: común, comet, shubunkin (tricolor), wakin (double flow), pray, ryukin, ranchu, Lion's Head, Moor/telescope eyes, bubble eyes, pearl scale y butterfly tailSome (oranda, lion head, ranchu) develop a cephalic cap which can grow with age and needs very clean water to avoid infections.
I hope that with this information you can learn more about the goldfish. If you guarantee enough space, stable water and a varied diet, you will have a striking, social and very resistant companion in both the aquarium and the home pond.
