Zebra danios (Danio rerio) will always hold a special place in my heart because they were the first fish I ever kept. While most people start out in the aquarium hobby by squishing a huge goldfish into a tiny fishbowl, I jumped straight into the deep end and bought a 5-gallon tank to fill with a school of fish. In hindsight, it was lucky I chose zebra danios, as they’re an incredibly hardy species that were barely fazed by my numerous early mistakes. And that’s what makes them such a great beginner fish—they’re incredibly difficult to screw up with.
| Zebra Danio Stats |
| Minimum Tank Size: 5 Gallon (10 Gallon Recommended) |
| Care Level: Very Easy |
| Water Conditions: pH 6.5-7.2 and Soft to Medium Hard |
| Temperature: 65-77 °F (18-25 °C) |
| Maximum Size: 2.5 inches (6 cm) |
In the old days, many aquarium books even recommended cycling aquariums using zebra danios. While the ammonia and nitrites would kill many other delicate fish (I’m looking at your neon tetras), the zebra danios usually emerged from cycling completely unscathed. Of course, we know now that fishless cycling is far superior, but it just goes to show how tolerant they are of poor water conditions.
But zebra danio toughness isn’t the only reason to own them. They are also an attractive fish, with interesting behaviours, and are happy eating just about any fish food. Once introduced to an aquarium, they will establish a pecking order, with the larger fish often claiming a territory. It’s always fun to watch them interact, though you’ll need at least six of the fish to experience this behavior (which also happens to be the minimum number recommended for an aquarium.)
Natural Habitat
Zebra danios are found throughout India and Nepal and are currently listed as Least Concern by the IUCN Red List. This means that while their population is declining—possibly due to the aquarium trade—they are not currently threatened.
In their natural habitat, they are found in streams, ponds, canals, ditches, and rice paddies. They prefer slow moving and even stagnant water, and the water is often choked with vegetation. In areas without any aquatic plants, they will often congregate near areas with overhanging plants.
Housing
If you’re going to keep zebra danios, then I always recommend using at least a 10-gallon aquarium. While many sites claim you can get away with using a 5 gallon tank, it’s really too small, and you’ll inevitably end up with water quality issues.
A zebra danio’s aquarium should have a sand or gravel substrate (aquarium grade only), and also plenty of aquarium plants to reduce stress. The plants have the added benefit of helping to filter the water and are often a godsend in a new tank. Decorations and driftwood can also be added, but just make sure they don’t have any jagged edges that can tear a fish’s fin. Also, make sure you leave enough open space, as zebra danios are very active and clear need areas for swimming.
Once your aquarium has been cycled, the plants have been added, and there’s a little bubbling treasure chest on the bottom (not actually required), then it’s time to add the zebra danios. You shouldn’t add them all at once, but in groups of threes to prevent any spikes in ammonia or nitrites. It’s important to monitor the water quality after adding new fish, and if you don’t want to buy a testing kit, you can usually get the water tested for free at a local pet store.
Feeding
One of the things I like the most about zebra danio is the ease of feeding them. While some fish like dwarf puffers make you want to tear your hair out as they spit out yet another new food, zebra danios will accept almost anything you offer to them.
In the wild, they feed on tiny crustaceans, worms, and insect larva. If you really want to make your fish happy—or you’re conditioning them for breeding—zebra danios should be a similar diet to what they eat in their natural habitat. Some easy to find live foods are gut loaded brine shrimp, black worms, copepods, and daphnia. Of course, they’re perfectly happy accepting any store-bought fish foods, but it’s a good idea to supplement their diet with frozen foods like blood worms, blackworms, and brine shrimp.
I recommend feeding zebra danios two-three times a day, and all the food should be gone after two minutes. If any food remains after that time, then you’re overfeeding them. And if you’re overfeeding then, you’re going to end up with algae and water quality issues.
Breeding
Zebra danios are incredibly easy to breed, but they will need a separate breeding tank if you want to raise the fry. While they will regularly scatter their eggs in an aquarium—usually following a water change, which tricks them into thinking the monsoon breeding season has arrived—they are notorious for eating their own eggs. If they’re kept in a community tank, it’s incredibly rare for any of their offspring to survive.
If you’re ready to try your hand at breeding zebra danios, then the first thing you need to do is set up a breeding tank. The dedicated aquarium should be fully cycled (this is incredibly important as newborn fish are very sensitive to water fluctuations) and empty except for a single layer of marbles at the bottom. The eggs will fall through the spaces between the marbles and keep them away from the hungry adults.
Once the breeding tank is ready, you should separate the male and female zebra danios into their own tanks. The females will have rounder and plump bodies, while the males will be more streamlined. After they’ve been placed in separate aquariums—within sight of each other—they should be fed high-quality food for at least a week. After a week has passed, the females should have plumped noticeably as their bodies begin to swell with eggs.
I usually wait until the next morning to add a pair of the zebra danios to the spawning tank. Then I leave them in until the next morning. Hopefully, they will have spawned by then, and you can usually tell by the female becoming noticeably thinner. But if it looks like the female didn’t scatter any eggs, then you can simply repeat with another pair until breeding occurs.
Tank Mates
I find zebra danios to be one of the best community fish in the hobby. They are tough enough to defend themselves against other fish, but generally leave even the most docile fish alone. That being said, fish with long flowing fins like guppies should be avoided, as zebra danios occasionally nip. Also, they will eat live-bearer fry, so unless you want to use them for population control, avoid them in molly and platy tanks.
Some of the best tank mates for zebra danios are corydoras catfish, tetras, rasboras, and many of the smaller barbs. They also do well with most loaches—even the large ones like weather loaches—and pleco fish.