Danio rerio
| Difficulty | Easy |
| Minimum Tank Size | 10 Gallons |
| Diet | Omnivore |
| Water Parameters | 64-75 F, pH 6.5-7.5 |
| Aggression | Peaceful |
| Size | 3" |
Zebra Danio are easily recognizable fish that can help bring out contrast when paired with more colorful tankmates. Their slender grey bodies and black stripes go well with lush green plants, colorful substrate and a dark backdrop.
These danio do well with small schools of six to ten fish. When alone they will swim around the tank, however they are much more active when in a school due to the safety they feel when surrounded by their own kind.
The Zebra Danio is a hardy fish, making it an excellent choice for aquarists of all experience levels. They do jump quite often, so a hood is required when keeping these fish. Cover any holes with a mesh net, as they can often jump out of cracks left in cut outs used for filters. Likewise they are much more likely to jump when acclimating to changed in the water parameters.
Behavior & Aggression
Zebra Danio will not fight with other fish, however there will be a bit of fighting among the school of danio at first. This will end in a day or so once the pecking order has been established. None of the danio should be hurt by this process, but it is always a good idea to keep a close eye on them when they are sorting out who is the most dominant.
If you are finding the danio to be too aggressive you can help lower the aggression by adding in ample hiding places. This can be in the form of aquarium plants, decorations, rocks or just a bigger tank in general. I prefer to use plenty of mid sized plants, as they have a lot of benefits to the tank other than providing cover. If you plan on using plastic grasses or plants be sure to check them for sharp edges. Some of these will come extremely sharp and can cut scales or rip fins. Round out any edges that are too sharp.
The one issue with Zebra Danio is their fin nippings. While they will often flare their fins and wiggle aggressively at others, they won’t start any fights. Still they do nip so avoid pairing them with fish who have large flowing fins like betta fish. The danio will use their speed to rush in, nip a fishes fin and slip away to defend their territory. They will only do this to large fin fish. Fish like mollies, rasbora and gouramis make for excellent tank mates.
Diet & Feeding
Being omnivores, danio will accept most prepared foods. Swap between frozen and prepared foods to help round out their diet. Their mouths have adapted to feeding off of the surface, so try to avoid food that sinks too quickly. Floating foods work best, but as long as the food does not hit the bottom of the tank the danios will have no issues getting it.
Danio are small enough that they will also eat any small organisms living in the water like copepods. If you have a colony of pods in the tank then keeping multiple danio may slowly wipe them out.
Breeding & Sex Differences
Zebra Danio genders can be distinguished by the shap of their bodies. Male bodies tend to be more slender for quick swimming while the females have a larger belly. Unlike many fish, male danios will often only have one female partner. This means you can have multiple pairings in one tank if you give them enough space. Danio will not form pairs if their is no available territory.
The fry are quite small, only 2mm at most and will feed on their egg sacs for the first few days. After that they will need to feed on microorganisms. This makes rearing them incredibly difficult, with the majority of success being in breeding facilities rather than the home aquarium.
Zebra Danio will breed when kept in a safe environment, with the temperature higher than usual. Increasing feeding and a regular lighting schedule will also increase breeding chances.
