Zebrafish (also called Zebra Danio) have become a favorite fish among hobbyists of all levels. They originate from the streams of the India and Pakistan areas. Due to modern breeding methods, this fish can survive in fresh water of almost any temperature. Your Zebrafish will not require a heater for their tank, but they do enjoy water that has a gentle current. A large tank is recommended for these playful and curious fish, as they spend their time swimming rapidly around their habitat.

Zebrafish are small, normally attaining a size from two to two and a half inches.

Most will live two to three years and with proper care, some may live to be four or five years old. Zebrafish are a schooling fish that thrive in schools of five or six and these numbers will keep aggressive behavior to a minimum. This fish will make a welcome addition to your tank and will get along with communities of other small fish.

a zebrafish swimming down from the top of the aquarium

Zebrafish Information

  • Average Length: 1.5 – 2.5 inches
  • Attention Needs: Low
  • Good tolerance to Heat and Cold: Yes
  • Good Pet: Yes!
  • Good with Other Zebrafish: Yes
  • Good with Other fish species: Yes
  • Suitable for First-Time fish Owners: Yes
  • Health Concerns: Intestinal Nematodes and Mycobacteriosis
  • Average Life Span: 5 – 7 years
a zebrafish swimming near an aquatic plant

Physical Appearance of Zebrafish

The fish have either silverfish or golden-looking bodies that are lined by bluish horizontal stripes that run from the head to the tail fin. The male fish tend to have a golden coloration while the females look silver-white. It’s also possible to differentiate a male and a female Zebrafish from their body appearance. The females have a round and bigger body while the male is slimmer with an elongated body.

There are other color variations such as the Albino, golden without any stripes, and the leopard spots Zebrafish. Breeders have also bred Zebrafish with veil tailed fins as well as some with extra-long fins. These unique looking strains of Zebrafish are common species in the aquarium hobby. Varieties such as the albino rarely make it in the wild because they become targets for predators.

Temperament of Zebrafish

The Zebrafish are peaceful and social fish that enjoy living in groups. If a Zebrafish is placed alone in a tank, it will likely become stressed and spend most of the time hiding among substrates in the tank.  It really needs a school of other Zebrafish to be happy.

They also tend to bite slow fish with long fins but don’t become overly aggressive. Zebrafish spend their time swimming in the middle to upper parts of the aquarium.

Zebrafish may also become aggressive if they’re under populated in the tank. The targets of aggression are usually lower ranking fish that get nipped on the fins. If you have groups of 6 or more Zebrafish in a tank, predatory behavior is drastically reduced.

Best Habitat for Zebrafish

Zebrafish originated from Asia’s cold waters and slow flowing rivers. You should try to mimic the fish’s natural habitat to reduce stress among your fish. Here are some of the requirements for an ideal habitat.

Tank size

The fish are very active and require enough space to swim with their species and other peaceful species. The best size for Zebrafish is a minimum of 10 gallon tank that can hold 6 – 8 fish. The general rule to follow is 1 Zebrafish for every 2 gallons of water.


Drastic changes in temperatures can affect your fish because in their natural habitat, the fish survive in very cold waters. The ideal temperatures for Zebrafish should be kept between 70-74° F, however they will do just fine as high as 90 degrees.

a school of zebrafish swimming together in a dark tank

Water Hardness and pH

The water hardness of a Zebrafish tank should remain at 5-12 dKH while the pH should be 6 – 8.


Zebrafish are active during the day and light is an important aspect for their home. The fish should have light for a minimum of 12 hours in a day.  It is a good idea to buy a lighting timer for your tank so that at night while you are sleeping the light will be off for the fish.

a zebrafish swimming near a plant


Zebrafish do well in tanks covered with green plants such as the Amazon Sword plants. Java Fern is also a good plant for your Zebrafish because it gives them a home similar to their natural habitat.

Cave looking substrates to give your pet a place to rest or hide when they want to. Fine sand is a natural material that is commonly found in the rivers where Zebrafish are most seen.  In addition to the sand, you can also have fine pebbles of gravel to mimic the rocky feel in rivers.

The complexity of your aquarium usually helps to reduce aggressive behavior among fish because they have hiding places and enough distractions. The decorations also serve the purpose of improving the aesthetic value of your fish tank.

Best Tank mates for Zebrafish

An aquarium filled with different species of fish is a sight to behold. Carefully choosing tank mates for your Zebrafish is however an important step to ensuring a peaceful co-existence. When choosing the fish, don’t go for big ones that can harass your Zebrafish. You should also not go for smaller fish that could be preyed on by the Zebrafish. Here is a list of some fish that live well with this fish:

a zebrafish swimming in an aquarium with a gray background

Tank Maintenance 

Each week about 10 percent of water in your fish tank should be changed. It is also recommended that every other week you do a 25 percent water change to keep it fresh. Use a siphon to remove any particles from the substrate at the bottom of your tank.

The pH of your water should be checked daily and adjusted accordingly. Sodium bicarbonate is used to increase the pH of the water. Water testing kit is a must have so that you ensure the water conditions are safe for your fish.

Filtration for Zebrafish is important because it creates water flow that the fish can play with just like they would do in their natural habitat.

a zebrafish swimming up from the bottom of the aquarium

Health Issues

Zebrafish have a very strong immune system and rarely become ill. The fish is however susceptible to intestinal nematodes and mycobacteriosis.  Here we’ll cover exactly how to identify the two diseases.


The disease is caused by different types of bacteria present in the water. The disease is also accelerated by poor water conditions and stress. It is more likely that your fish has contracted the disease if you observe the following symptoms.

  • Lethargy
  • Anorexia
  • Fin loss
  • Skin inflammation

The disease spreads very fast in an aquarium and the first measure should be removing the sick fish from the tank. Most microbial treatments for the disease don’t work and sadly you might  lose your entire tank if you don’t take immediate measures.

Water changes and disinfection could help salvage the situation. As you go about cleaning and disinfecting the tank, it’s important to know that Mycobacteriosis can infect humans. It is very important that you wear some protective gloves before handling the water in the tank.

Intestinal Nematodes

The illness is caused by a nematode worm and is a common disease among Zebrafish. Sick fish appear lethargic and lose weight fast. The fish may also appear darker in color. A fish with intestinal nematodes should be separated from the rest for treatment.

Feeding Zebrafish

The fish are omnivorous and can eat meat and vegetables. The most common food for Zebrafish is fish flakes and pellets. The flakes are readily available in the pet stores and make a delicious meal for fish.

You should give your pet live foods such as Bloodworms or Daphnia at most once a week. Finely shredded vegetables such as peas, cucumbers, and spinach also help nourish your Zebrafish. In some cases, you may not find live foods in the pet stores. If this is the case, you should buy your fish dried or frozen Bloodworms or Daphnia.

The fish should be given only what they can eat within two minutes once or twice a day.  Any more will result in overfeeding them.

Related Questions:

Do Zebrafish Mate?

Unlike most fish species, Zebrafish can pair and remain mates for life monogamously. The fish tend to chase each other around the tank whenever they want to mate. The behavior is mostly seen in the mornings.

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