One of the common fish in any aquarium is the zebra fishThere is a wide variety of this type and it is known to be the first vertebrate to be cloned. Its scientific name is Danio laughed (historical synonym Brachydanio rerio). It is an actinopterygian osteichthyal fish, it belongs to the order of Cypriniformes and its family is Cyprinidae. In this article we are going to talk about its characteristics, feeding and care necessary in aquariums, in addition to expanding useful information about their breeding and their role in science.
Would you like read more about zebrafish? Read on.
Key features
They are fish with a length of about 5 centimeters (up to 6 cm in good conditions). The body is elongated and fusiform, designed for effortless swimming. Unlike other fish, it only has a dorsal fin and a slightly superior and upward-facing mouth. This is caused by a lower jaw protractile which helps it capture food on the surface. It has a pair of very fine barbels that are best seen when the animal stands on vertical positionThe eyes are centrally located.
It has no real teeth or a defined stomach and feeds using gill rakers (spiny gills) that filter and suck in food. Along the side, you can see between 5 and 9 dark blue stripes that run from the head to the caudal. The operculum shows bluish reflections, and the ventral area is white with a pinkish hue. These longitudinal stripes are what give the zebrafish its name.
Presents sexual dimorphism obvious: in general, the female is larger, with a more swollen belly (due to unfertilized eggs) and a silvery background tone; the male is somewhat smaller and looks golden huesThis coloring pattern, besides being eye-catching, acts as camouflage against predators: the light belly blends in with the light from below and the darker back blends in with the background when seen from above.
There is a very popular variant called zebra leopard, with mottling instead of stripes, which comes from a stable mutation. It is not a distinct species but a form of the same Danio laughed, so their care is the same.
Range and habitat
This species is native to the streams located in the southeast of the region of Himalayas and it is in India, Pakistan, Bangladesh, Nepal and Burma. Large populations are found in these areas, especially in tributaries of the Ganges system. It also appears in rice fields, where water damming and irrigation systems generate shallow, well-oxygenated water bodies that the zebrafish uses to live and even reproduce.
In its natural habitat it occupies streams, ditches, canals, ponds and other bodies of fresh water. slow current or stagnant. It tolerates human presence well and easily coexists in transformed environments, which explains its popularity in aquariophilia. Due to seasonal floods, it has adapted to a wide thermal range, from cold to warm temperatures, being able to survive between approximately 18 and 29 °C in nature.
Through translocations and escapes, introduced populations have also been recorded in other countries, such as some states in the United States, and in parts of South America. It is important to remember that should not be released aquarium fish to the natural environment.
In conservation, Danio laughed It is listed as Minor Concern on a global scale, although local populations may fluctuate depending on habitat quality.
Behavior
The zebrafish is an animal social and very active whose activity takes place mainly during the day. It moves in shoal and establishes hierarchies, especially among males. Dominant individuals may show territorial behavior temporary during courtship, with chases and small nibbles to delimit the spawning area.
When they form a group, they swim in a synchronized manner and change direction instantly without colliding with each other. coordinated turn confuses predators, creating the impression of a larger organism. When threats are detected by sight or smell, increase agitation, reduce feeding and exhibit warning signs to the rest of the group.
For their well-being in the aquarium, it is ideal to keep them in groups of 8 to 10 or more (minimum 6), as this number reduces stress and encourages natural behaviors. Another key feature: they are excellent jumpers; it is always advisable to cover the aquarium.
Zebrafish feeding
The diet is omnivorousIn the wild it consumes zooplankton, small crustaceans, mosquito larvae and insects that fall to the surface. It may also ingest phytoplankton and small worms when available.
Since it lacks a true stomach, it makes better use of small, frequent portions. In aquarium it accepts without problem micropellets good quality, fine flakes, and live or frozen food such as daphnia y Artemia. Two or three small daily doses are ideal. One day a week of light fasting helps prevent digestive problems.
It is guided by the sight and smell to capture food, so it is advisable to offer food in open swimming areas with a adequate lighting of the tank. Alternating types and textures enhances coloration and stimulates natural foraging behavior.
Reproduction
The zebrafish reaches the sexual maturity between three and six months and is capable of reproducing all year round. Fertilization is external and usually occurs at dawn. The female may release 200 to 500 eggs in optimal conditions, especially if well conditioned with live food and a balanced protein diet.
After fertilization, the eggs normally hatch in 2-3 days depending on the temperature. From the fifth day after hatching, the larvae begin to exogenous feeding; respond very well to infusoria, rotifers and nauplii of Artemia newly hatched. The metamorphosis from larva to juvenile is usually completed around the third week.
This is a spawner asynchronous, which allows you to organize groups in batches and schedule staggered installations. smell influences mate choice and, when possible, females tend to avoid mating with closely related males.
Practical home breeding tips: You can use pairs or trios (for example, 1 female and 2 males) in a container of 10 liters for one batch or 40 liters for several batches. Place marbles or mesh at the bottom to protect the eggs from the adults and remove the parents after spawning. Keep the pH close to 7,0 and temperature around 24-26 ° C (28-28,5°C is often used in laboratory settings to accelerate development). For fry, start with infusoria and progress to Artemia or very fine scales as they swim freely.
Necessary care
These fish are calm and easy to maintain. Since they live in schools, it is important that the aquarium has minimum 6 copies and, if possible, 8 to 10 or more. This makes for a colorful and stress-free community aquarium.
The aquarium must offer swimming space without obstacles, especially in the upper area, with densely populated areas planted for the shelter. The gravel should be fine, without sharp edges that could harm the fish. A biological filter efficient; a rule of thumb is a combined flow rate of 5-10 times the aquarium volume per hour, with a circulation that generates moderate current and good oxygenation, leaving rest areas.
As for volume, for a small group you can start from 60-80 liters, but for a school of 10 fish or more it is preferable 80-100 liters or higher. Many specialized sources recommend not going too low: the higher the volume, the more stable the system will be.
Water parameters: Wide accepted range with pH of 6,8 to 7,5 (for fine reproduction they are usually preferred 6,8-7,2), general hardness between 5 and 15 °dGH (soft to medium water best, below 20 °dH) and temperature between 18 and 26 ° C for general maintenance, occasionally allowing temperatures up to 28-29 °C. In temperate homes, the aquarium can be operated without heater if the room temperature remains stable within the appropriate range; in summer it is advisable to ensure that it does not rise too much.
Performs partial changes weekly 25-40%, maintain a photoperiod of 10-12 hours and cover the aquarium because they are jumpers. Avoid overcrowding: In research environments it has been proven that densities above 40 fish per liter They generate significant stress; in home aquariums, much lower densities are used, prioritizing well-being.
To preserve traits and health, it is not recommended mix varieties or species of the same genus indiscriminately, as hybridization may occur. Before introducing new fish, respect the quarantine and make sure the aquarium is fully cycled.
Compatibility
The zebra danio is a cyprinid peaceful that coexists very well with other species of similar size and active temperament; take into account the preferences of cold and warm water fishAvoid very slow-moving or long-finned fish, which can be stressed by their dynamism on the surface.
Compatible fish
- Guppies
- Molly
- Corydoras
- neon tetra
- Little nuns
Fish not recommended: : very slow species or those with very developed fins (for example, some bettas or veiltails) and aggressive species that stress them.
Scientific and educational importance
The zebrafish has established itself as biological model in research due to its high fertility, transparent embryos that allow you to see the development, small size and low maintenance cost. It shares approximately 70% of genes with humans, making it useful in studies of developmental biology, toxicology, immunology, and more.
In controlled laboratory environments, temperatures of 28-28,5 ° C and feeding protocols with very frequent small rations due to their lack of stomach. When designing professional breeding systems, care is taken lighting Because zebrafish use sight and smell to feed and reproduce. Educational programs take advantage of these characteristics to bring science closer to students with direct observations of embryonic development.
FAQs
How to differentiate males and females? Males are more stylized and may show golden tones; females present bigger belly and a silvery tone. That volume is not pregnancy: it is eggs that they will release during spawning.
Do you need a heater? Not always. If your house is kept between 18 and 24 ° C stable, they can live without heating. If the temperature drops steadily, use a heater; if it rises sharply in summer, reinforce the ventilation and controls the temperature.
How to feed fry? The first few days after hatching they consume the yolk sac. From the fifth day, offers infusoria or rotifers and gradually moves on to Artemia newly hatched. Keep multiple microtomes daily for homogeneous growth.
With proper aquarium planning, a large and active school of fish, well-filtered water and a varied diet in small portions, the zebrafish displays its full potential. vitality and colorful. It is an ideal option for beginners, with room to delve deeper into breeding and development observation, which explains its enormous success among amateurs and scientists.
