Tetras are not the first fish to come to mind in terms of easy breeding, but some are easier to breed than you might have been led to believe. One longtime aquarist provides his tried-and-true method of breeding tetras, suggesting five species to start with.
Very few aquarists include characins in the category of easy-to-breed fish. If we compare them to many livebearers and cichlids, they are not easy to spawn. There are many species of tetras, however, and some of them are easier to spawn than others—in fact many hobbyists have tetras spawning in their community tanks, though the fry seldom survive. I’ll cover the basic methods for spawning these fish and finish up with a quintet of tetras that are among the easiest.
Most of the smaller tetra species from South America are not reluctant to lay eggs. Conditioning females does not require much more than a good supply of quality foods and decent water quality. Triggering pairs to spawn can be as easy as turning on the lights or doing a cool water change. The challenge of raising tetras usually comes with successfully rearing the very small fry.
A Basic Strategy for Success
There are several methods used by successful aquarists for spawning small egg-scattering characins. This strategy uses a single pair—two fish that are well conditioned and ready to spawn. Spawning larger groups of tetras is possible, but that presents some problems that are negated by working with just a few fish. Larger schools of fish require more space and produce larger numbers of eggs. How many fry are really needed? Even the smallest tetras are capable of producing several dozen eggs in one spawning attempt. When large groups are kept together for spawning, not all of the fish are actively involved. Those that are not breeding are usually eating eggs.
The first step is to condition a school of small tetras. This can be accomplished in a community tank. High-quality flake, crumble, and freeze-dried foods are excellent staples, but faster results will be achieved with live foods. Worms such as Grindal, white-, and blackworms are the conditioning foods of choice for most serious breeders. Daphnia are also excellent for bringing fish into spawning condition. Female tetras that are ready to spawn will be quite plump with eggs several hours after feeding. Most tetras spawn in the morning shortly after the lights are turned on. One way to determine if the fish are ready to breed is to turn on the lights an hour or more before the fish are fed. If the fish are engaged in courting (or even spawning) in the community tank, then they are ready to breed in the spawning tank also.
A bare-bottom 2½- or 5-gallon tank is all that is needed to breed small tetras. Fill the spawning tank with water from the community tank the fish were conditioned in. A small, air-driven sponge filter is adequate filtration. So long as the temperature of the tank is stable in the mid-70s, a heater is not needed. If the aquarium is in a drafty area or cool room, a small submersible heater will be needed to help the eggs and fry develop and grow. Sink a large mass of Java moss or yarn spawning mop in the tank. This structure is where the pair will scatter their eggs. Use enough moss or yarn to fill at least ¾ of the tank space. Move the female of the spawning pair into the spawning tank by herself. Leave her there by herself for two days, and only feed her a small amount.
An attempt to spawn the pair begins the evening before the actual spawning will occur. Start with a 50-percent water change in the spawning tank using slightly cooler, aged water. Use reverse osmosis (RO) water if it is available, but it is not absolutely necessary. Tap water that has been dechlorinated and aged will work, as well as water siphoned from the community tank and cooled to room temperature for a day. Move the male from the community tank to the spawning tank after doing the water change. Turn off the lights over the tank, and if the room is bright, cover the tank with a dark towel.
Uncover the tank in the morning and turn on the lights. Do not disturb the pair for a few hours, and then check for eggs. Most tetras lay a clear egg that is slightly smaller than one millimeter. Adhesive eggs will appear in the moss or yarn mop. Non-adhesive eggs will filter through the structure and lay on the bottom of the tank. A flashlight will make the eggs easier to see. If there are no eggs present, leave the pair alone and check again in a few hours. If there are no eggs by the end of the day, turn the lights off and try again the next day. If there are no eggs after two days of trying, do another water change and try for the third day. If the pair still does not spawn, put them back into the community tank and try again with a different pair, or wait a couple of weeks and try again with the same pair.
When eggs are present in the spawning tank, move the pair back into the display tank right away. A pair will eat their own eggs, but not usually the same day they lay them. Many aquarists add a few drops of methylene blue or acriflavine to the spawning tank to protect the eggs from fungus and darken the water a bit. Leave the lights over the tank off, and if the room is bright, cover it with the towel again. The eggs will take at least 48 hours to hatch and another couple of days for the larvae to become free-swimming (depending upon temperature and species). It is best not to disturb the tank during this time. If the eggs and fry are light sensitive, shining a light into the tank to check on them may cause harm.
The First Week Is the Most Critical
Five days after the eggs are laid, add a source of very small food to the fry tank. Use a few ounces of green water, but if that is unavailable, use some vinegar eels. If neither of those live foods is available, the next best choice is “sponge grunge.” Carefully lift the sponge filter from the fry tank and squeeze it in the tank water. This will release millions of microorganisms from the sponge into the water where the fry can get at them. Commercial fry foods can be used, but they do not contain the living things that trigger the very small fry to feed. Microworms, an excellent live food, are often too large for the very small fry and should be saved for feeding later.
The first week will be the most critical in the lives of the new tetra fry. If they can get enough food to grow to a size that allows them to eat larger types of food, then they stand a good chance of surviving. Do not give into the temptation to feed larger foods like fry powders, microworms, or Artemia nauplii (baby brine shrimp) too early. A few fry might be able to eat the larger particles, but most of the fry cannot. The extra food will just rot and cause other problems.
Feed small amounts and do not change the water during this first week. At the end of the week, do a small water change (10 to 15 percent) with aged water. Start turning on the lights over the tank, but arrange things so that only about half the tank is lit to provide a shaded area for the fry. Start feeding some microworms and begin looking for fry that are eating enough to get a full belly.
Two- to three-week-old fry will be large enough to start eating baby brine shrimp and commercial fry foods. Water changes are important from this point. A daily change of 30 percent, combined with a few feedings every day, will result in the fry growing very fast. It is not uncommon for fry to triple or even quadruple their size during their third and fourth week after becoming free-swimming.
Healthy Growth Requires Adequate Space
At some point, the fry will need to be moved to a larger tank. A hundred fry can be raised up to half an inch in a 10-gallon tank, so long as plenty of water changes are done to keep the water fresh. If doing daily changes of 40 to 50 percent is not possible, then a larger tank will be needed to raise that many fry. The other option is to avoid raising hundreds of fry. Move 20 to 30 fry from the spawning tank to a 10-gallon to grow out. The other fry in the spawning tank can be fed to the community tank. This may seem cruel, but it is actually realistic. The majority of fry in nature become food for larger fish. The few fish moved to a grow-out tank can stay there until they are large enough to join their parents in the community tank or be given to other aquarists.
Five Species to Start With
Ember Tetra Hyphessobrycon amandae
The ember tetra grows to just about an inch in length. They are amber yellow with orange highlights and school together well, even in small tanks. They are popular schooling fish for planted tanks and make excellent dither fish for peaceful dwarf cichlids or small anabantids.
Female H. amandae are notably rounder than the males and are very prolific. The eggs are non-adhesive and not light sensitive. The fry grow slowly, however, and may take as long as two months to reach ¼ inch. Softer, more acidic water will improve the ember tetra’s colors, and it may also help with the spawning process. So long as the water is not too hard (above 250 ppm TDS) or too basic (above 7.4 pH), this species is not hard to breed.
Glowlight Tetra Hemigrammus erythrozonus
This beautiful tetra has been a staple in the hobby for many years. Most of these fish in stores are wild-caught, but they are some of the easiest and most prolific tetras to spawn in an aquarium. A single female can produce 50 or more eggs in one spawn. The fry are hardy and grow very fast. This species is also an excellent schooling species for planted tanks and an outstanding dither fish for dwarf cichlids.
Emperor Tetra Nematobrycon palmeri
The emperor tetra is a showy species in which the males grow larger than 2 inches. Males defend territories and display for the attention of the females. The females will form loose schools, especially in larger tanks. This tetra makes a good centerpiece species for planted tanks. It is also hardy enough to be useful as a target or dither species for dwarf cichlids that might take a swipe at it every now and then. Emperor tetras spawn easily as a pair, and the fry are fast growers. Juveniles take six months to grow into their adult glory, but they are worth the wait.
Black Phantom Tetra Hyphessobrycon megalopterus
The subtle beauty of this high-fin species is best appreciated in large groups. The males’ long fins are often extended in territorial display. A school of a dozen or more is an impressive sight. The females condition quickly and can easily produce a hundred eggs in a single spawn. The fry are very small, however, and will need green water and vinegar eels for a little longer before they can take the larger foods that will help them grow quickly.
Pristella Tetra Pristella maxillaris
This robust, colorful, and inexpensive tetra is one of the best species for a beginning fish breeder to work with. The females are almost always in condition to spawn and more than willing to scatter eggs. The fry are hardy and grow fast.
No Matter the Reason, Breed Tetras
How hard is it to set up an extra 5-gallon tank to spawn a small tetra? A hobbyist with one large community tank can have a lot of fun building a big school of tetras from a small purchase of three or four fish from the pet shop. An aquarium club member could participate in their club’s Breeder Awards Program just by rotating different species from a show tank through the breeding tank. Maybe the local aquarium store will take a dozen fry in for a few tetras of the next species the aquarist wants to work with. No matter what the reason, breeding tetras is easy, fun, and rewarding.