How to Breed Black Neon Tetras

black neon tetra
Black Neon Tetra Tank

Unlike the neon tetra, black neon tetras are relatively easy to breed, even for the novice aquarist. When kept in adequate conditions, black neons may spawn on their own, but the resulting eggs and fry can also end up as snacks for the adults in the tank.

For those interested in breeding their black neons, setting up a separate spawning tank is the best practice.

Black Neon Tetras: Collection in the Wild

Native to the Paraguay and Taquari River Basins of southern Brazil, the ornamental fish trade caused some black neons to end up introduced to the Minas Gerais River Basin; a feral group also ended up in the Rio Paraiba do Sul River Basin.

However, due to the ease of breeding black neons in captivity, almost all are now farm-raised. There is also an albino version available in some areas, but it’s rare.

Black Neon Tetras: Aquarium Overview

To get the best yield of fry, set up a separate spawning tank for your selected black neon breeders. A 10-gallon tank is a sufficient size, equipped with an air-powered sponge filter for water flow. Aquarium-safe peat will provide sufficient filtration as well as helping to encourage spawning.

You can use fine-texted, live plants to provide structures for the eggs to attach to, as well as floating plants to cut down on the light in the tank. Plants will require a substrate to root into, and they will take 2-3 weeks to properly fill in the tank. It’s best to utilize natural substrates, avoiding any synthetic materials (gravel coated with epoxy, glass beads, colored ceramics, etc.). When building substrate for your plants, follow these guidelines:

  1. Mix the first layer with fertilizer (less is more – you won’t need a lot) and place in the tank.
  2. Place a bowl or plate over the bottom layer to keep from churning the fertilizer into the water column.
  3. Add up to 2 additional layers, starting with the finest granules (i.e., sand up to larger substrate types). You can remove the bowl/plate once that first layer is down.
  4. You want a depth between 3-8mm (0.1-0.3in), depending on how deep-rooted your plants are. Some plants need a root depth up to 6cm (2-3in), so research your plants carefully!
Plant Examples by Root Type
No Sand NeededAnubias, Microsorium, Bolbitis
Large RootstocksAponogeton, Nymphaea
Long Stems, Shallow RootsHygrophila, Rotala
Deep RootsCryptocoryne, Echinodorus
Tank plants
tank plants

If you’re interested in a planted tank, consider picking up Diana Walstad’s Ecology of the Planted Aquarium for the best information.

Another option is to go with a “minimalist” tank and avoid plants altogether. This method involves using nylon spawning mops: two at the bottom and one at the top. The mops won’t break down in the water, and they’re easy to clean.

Either tank will serve the same function – providing attachment for the sticky eggs.

Black Neon Tetras: Water Quality

Before introducing either your breeding black neons or any plants, it’s important to thoroughly clean the tank you plan to use. A salt solution (no table salt, please) works great as a mild disinfectant, followed by a rinse with tap water. The tank should then be filled with dechlorinated water and allowed to fully mature.

Black neons tolerate water conditions outside of their normal environment, but if you want to encourage successful breeding, you should aim to emulate their natural habitat. This means soft, acidic water. Ideally, you want the following conditions:

  • pH: No higher than 7.2
  • Hardness: Maximum of 6dGH (aim for 4 or less dGH)

Black Neon Tetras: Lighting

The eggs of black neons are believed to be light-sensitive, so it’s important to keep your spawning tank dim. Many fish farms breed black neons in complete darkness, but this isn’t practical for most aquarists.

If the room you’re using is bright, you can cut down on the light by covering the sides of the tank with cardboard, towels, or newspaper. This will help create the subdued lighting the eggs prefer.

Black Neon Tetras: Temperature

Again, while black neons accept a wide range of water conditions, spawning tanks should strive to mimic the waters of the Amazon. When the selected pairs or groups of breeders are first introduced to the tank, the temperature should be around 75F (24C). After a few days, it should be increased to 80F (26.7C) for optimal breeding conditions.

If you’re having trouble maintaining adequate temperature, you can try covering the top of the tank with a towel to help retain warmth.

Black Neon Tetra
Black Neon Tetra

Black Neon Tetras: Pair Selection

Now that your spawning tank is prepared, it’s time to choose your breeders. Black neons will breed at a young age, but, ideally, you want to wait until they’re fully mature (at least one year); you’ll get better results.

It can be a little difficult to determine males from females, but female black neons have a larger, more rounded belly than males.

When making your selection, follow these general guidelines:

  • Choose males that have the brightest coloration
  • Females that are ready to spawn will have a “fatter” belly
  • You want one or two males and a small group of females

To give your breeding group the best chance for success, condition them with live foods before the anticipated spawning time. This provides them with the best resources, and it will improve your chances of success.

Brine shrimp are one of the best live foods available, and they come in a lot of different brands. The brands are based on the kinds of food they’re fed, providing different “flavors” for your black neons. If you’re up to the task, you can also purchase dried brine shrimp eggs, hatching and setting up a colony of your own.

Other live foods you can try (after all, not all black neons will like brine shrimp) include:

  • Earthworms
  • Grindal worms
  • Maggots
  • Microworms
  • Mosquito larva
  • Vinegar eels
  • Wingless fruit flies

If obtaining live food is too difficult (or expensive) you can try the frozen versions. Try to make sure you offer a variety, though. (After all, who wants to eat the same food every day?) Plus, a varied diet is healthiest for your black neons.

Black Neon Tetras: Spawning

Black neons may spawn year-round, but their prime spawning time is the spring and summer.  This coincides with the natural spawning time in the wild. Insect hatching surges during the spring, so there’s a boom of insect carcasses in the water, making for an abundance of resources (hence why it’s a good idea to condition them with live-feeding). Black neons will usually spawn first thing in the morning.

The females’ bellies enlarge as they fill with eggs, and the males will become livelier. During spawning, the male will “dance” around the female and try to get her to follow him into the spawning mops or plants. Eventually, the pair will brush against each other, and the female will shed the eggs which are immediately fertilized by the male. The fish will swim in and out of the mops/plants, repeating this process. The entire spawning process takes about 1.5-2 hours.

When the female has finished, she will be much thinner, and she will duck into the mop/plant to hide from the male. The pair will need to rest through the next day. At this point, you should remove the breeders from the tank. They will be hungry to replenish their resources, and they may decide to ingest their new eggs.

Black Neon Tetras: Eggs

A single black neon female can lay between 100-200 eggs. The eggs themselves are tiny, transparent, and adhere to the provided surfaces. It’s a good idea to keep the tank as dim as possible while the eggs are incubating. They will hatch about 22-26 hours after they’re laid.

The fry are not initially free-swimming; they remain stationary while they feed off their yolk sac. They will not move from their hatch site until they have completely absorbed the sac – about 3-4 days. At that point, you should see the fry start to move about the tank.

Black Neon Tetras: Initial Food

Black neon fry are relatively easy to care for and raise. Their tiny bodies have a high nutritional demand, though, so it’s important to provide them with critical nutrients. The best foods to start include infusoria, freshly hatched brine shrimp, green water, or egg yolk. All of these should be prepared well in advance of hatching so they can be immediately introduced into the spawning tank; newly hatched fry can starve to death rapidly.

Infusoria is a collection of microscopic organisms naturally occurring in water, especially water with live plants. The spawning tank likely won’t have enough infusoria to support your fry, though, so you’ll need to set up a culture of your own. You DO NOT want to collect water from a local pond or puddle for your infusoria; such water harbors dangers to your newly-hatched fry. Pond water includes hazards such as:

  • Water fleas
  • Damselfly nymphs
  • Dragonfly nymphs
  • Hydra
  • Planaria
  • Water boatmen
  • Water tigers

If you want to culture your own infusoria, you’re better off avoiding such water sources. Instead, you can easily start a healthy culture with your community aquarium water. Set up a full glass jar (quart or gallon – whichever size you have available) in sunlight. Next, add some healthy medium to encourage the microorganisms to grow. Suggestions include:

  • Banana peel
  • Grass
  • Blanched or dried lettuce
  • Powdered cereal
  • Rabbit pellets
  • Raw potato
  • Boiled rice
  • Straw
  • Yeast

Allow your mixture to sit for several days. You’ll see the water turn cloudy, and you might even see the infusoria moving around. Once the culture is established, you can siphon off a few ounces (be careful not to get any of the decaying medium) and drop it into the spawning tank to feed your fry. Replace the same amount of treated freshwater to keep the culture cycling.

Brine Shrimp
Brine Shrimp

Freshly hatched brine shrimp are extremely nutritious for fry. If you’ve established a colony of your own, they’ll be available and ready for use. If not, there are commercially-available options, or you can always purchase frozen brine shrimp.

Green water is what it sounds like: water with microscopic algae growth which has turned it a characteristic green color. This is a great initial food for fry, and, like infusoria, it’s easy to prepare ahead of time. Using a glass jar (quart or gallon size again), fill it with water from your community aquarium and add a little scrape of algae from the side of the tank. If you don’t have any algae in your tank (awesome job – you’re keeping it clean…or your fish are), you can add some grass clippings. Add a couple of drops of fertilizer and set your jar in the sunlight (it can keep your jar of infusoria company). Within a few days, your jar should be a nice shade of green, and it will be full of microscopic algae. Like the infusoria, take a few ounces out for each feeding of your fry, replacing it with treated freshwater to keep your green water cycling.

Egg Yolk isn’t an ideal food for fry, but it does pack some protein, and if you haven’t prepared the other options, it’s a lot faster to get ready. Hard boil an egg and remove the yolk, wrapping it in some gauze. Compress the yolk through the gauze until only tiny pieces pass through. You can then hang the gauze in the tank for your fry to feed from. Make sure you replace it daily.

You can also purchase commercial fry foods – there are a lot of varieties out there. These are designed for larger fry, though, so consider setting up your infusoria or green water culture to start.

Fry should only be fed minute amounts of food – remember, they have tiny mouths! Feed them at least twice a day – several is better.

Black Neon Tetras: Fry Growth

At first, black neons are gray with black horizontal stripes. When they reach one week of age, they are old enough to graduate to eating brine shrimp nauplii, and you can start to add in finely-crushed dry foods. A quarter of their tank’s water should be changed out weekly to keep them healthy.

By three-weeks-old, their gray gains the shimmer and sparkle of the adults, the black stripe appears, and their eyes start to change color. By now, they should be able to eat the same diet as their parents. When they reach 3mm (0.1in), consider transferring them to a larger tank, especially if you have a large number of fry you’re trying to care for.

At five weeks, the black neon juveniles look like the adults in coloration. They should be large enough to move into the community tank, but take size into account – if they’re still small enough to be swallowed by someone, continue to keep them separated.

Black Neon Tetra
Black Neon Tetra

Conclusion

Black neon tetras are fairly easy to breed, making them an attractive hobby for novice and accomplished aquarists alike. Setting up a spawning tank can be as simple as a tank with spawning mops or as complicated as a planted tank with a dark substrate.

Raising black neon fry requires some prep work in the form of establishing infusoria or green water cultures, but they are otherwise easy to feed and care for. With a careful investment of time and preparation, breeding these striking fish can make for an exciting hobby.

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