How to Care for Zebra Danios

Setting Up the Aquarium

Choose a tank large enough for a group of fish. Danios thrive in groups, the larger the better. Ideally you should have at least five or six danios, in a tank that holds at least 25 gallons (95 liters). A group of three fish in a smaller tank is acceptable, but can lead to stress or aggression. Never keep a zebra danio alone or in a tank smaller than 10 gallons (38L).

Add gravel and plants. Add a layer of well-rinsed sand or gravel to the base of the dry tank. Add a few plants and ornaments as well, but keep the taller ones at the perimeter of the tank. Danios are active fish that need plenty of room to swim at the mid-level of the tank. The decorations are necessary so the fish can hide, but should not interfere with movement.

Add the water. If you are not familiar with aquarium care, read this article for more details. You may need to treat the water with a dechlorinator.

Set up aquarium equipment. A filter, air pump, aquarium light, and thermometer are standard supplies for any aquarium. Danios prefer temperatures around 77–82ºF (25–27ºC). Depending on the temperature conditions of your home, you may need a heater to regulate this temperature. Danios like water movement. Make sure there is water movement from the water filter.

Cycle your tank. It is very important to "cycle" a new aquarium for at least a month (not a day like some pet stores say!) before adding any fish. Use a test kit from an aquarium store to measure the amount of ammonia, nitrites, and nitrate. Do not add the fish until these measurements are stable at safe levels. Your test kit can also measure water pH (acidity). Danios do best in water pH from 6.5-7.2.

Add freshwater salt (optional). Some hobbyists add freshwater aquarium salt to their tanks in small amounts, as directed on the product label. This is a little controversial among aquarium owners. A little salt can help the fish fight off disease, but too much can have unwelcome side effects. Only use freshwater aquarium salt, not ordinary salt. Do not add salt more than once between water changes. Salt does not leave the tank, so adding more can cause a lethal overdose.

Caring for Zebra Danios

Acclimate the fish. As with any fish, danios should be introduced to the new tank slowly. Turn off the aquarium lighting and slowly introduce the aquarium water to the new fish's environment. The drip tube or floating bag methods are both good options. Danios are social animals that like to be in the company of other fish. A group of 6 or more is optimal. Danios get along with some other varieties of fish as well, including corydoras and tetras. If you have a large tank, introduce the new fish two or three at a time. Wait a week or two between introducing groups. This minimizes the disruption to your tank's chemistry, as well as stress on the fish.

Keep them separate from aggressive fish. Zebra danios are not aggressive, so you can safely add smaller fish to the same tank. Avoid adding any aggressive fish species to the same tank. Although zebra danios are peaceful, they are active swimmers. Some fish species may prefer a calmer environment. Danios may be "fin-nippers", especially when they are not schooled with other fish. A good aquarium store should have employees who can advise you on compatible species. Guppies, minnows, tetras, swordtails, corydoras (commonly cory cats) are good examples.

Feed in small amounts only. Zebra danios do not need any special feeding care and are not picky eaters, but overfeeding is a common cause of problems for all aquarium fish. A fish's stomach is about the size of the fish's eye. Each danio should only need a couple bites of food each feeding, 2–3 times per week, but can be fed each day if the other fish in the aquarium need feeding each day. Overfeeding can cause bloating as well as harmful chemical build-up in your water. Only feed the fish as much food as they can eat in 3 minutes. This is a general rule for all freshwater aquarium fish.

Maintain tank temperature. Danios are hearty and are comfortable in temperatures from 65 to 75 Fahrenheit. You can often maintain this temperature without a heater, but a heater will help. A slightly higher temperature, 78 Fahrenheit, is optimal for encouraging breeding.

Clean the tank weekly. When you clean the tank, you do not need to remove all of the gravel, however, you should use a siphon to suck up the waste that accumulates on the bottom of the tank. Use a scrapper to remove algae from the glass on the tank. After finishing these tasks, remove and replace 10-15% of the water. Do not remove fish when changing the water, this will cause unnecessary stress. When replacing the water, put new water into a bucket that is exclusively used for this purpose (If you use it for household tasks it might accumulate dangerous chemicals). Test and treat the water as discussed previously. Use a siphon to slowly introduce the new water back into the tank.