The emperor tetra (Nematobrycon palmeri) most likely got its common name because of its regal colors. Photo Credit: Gary Lange

You've probably heard that tetras are hard to breed. If we were talking about the cardinal tetra (Paracheirodon axelrodi), then that would be true. However, I would like to tell you about a group of tetras that is very easy to breed and requires just a little work to obtain fry. I call the technique I use the "lazy man's method." I find this method especially useful for keeping my "emperor-type" tetras. I find these fish so beautiful and easy to breed that I keep the four species going on a continuous basis.

There are essentially four groups of emperor-type tetras that are available in the hobby, and they can all be bred using the "lazy man's" approach. They are all less than 2 inches in length and fairly peaceful. If you have water that is lower than 200 ppm GH, you can probably produce fry without any effort. These tetras are small enough that you can keep a colony of 10 to 12 fish in a 10-gallon tank. A 15- or 20-gallon long tank makes an even better display. I keep my fish in a bare-bottom tank with a high-quality sponge filter built with the sponge kept off the bottom. Each tank is species specific. I cover the sides and back of the tank with dark contact paper on the outside and have also painted the outside bottom black. Because I have active, hungry rainbowfish in tanks next to them, I don't want my graceful tetras to be disturbed. The temperature ranges from 75 to 80 degrees Fahrenheit, depending on the season. All the tanks have moderate lighting (10 to 15 watts) and in theory get a 40-percent water change every other week. All have a nice growing layer of java moss in the back portion of the tank.

About the Author Gary Lange has been keeping fish since the second grade, and his interest in fish (and nature) eventually led him into the field of science as a career. He has been part of the organized hobby since 1982, and has been active in local and national aquarium societies.  His true love is the rainbowfish, from New Guinea and Australia, and he gives several talks a year about them. He has also kept and bred many other small fishes, usually under the length of 4 inches. Most of his aquariums contain plants as well as fish, and he has supplied Aquarium Fish Intl. with many pictures of both. He is currently employed as a biochemist for a major pharmaceutical company.

The first type is the "original" emperor tetra (Nematobrycon palmeri). Their regal blue and purple colors are most likely how they got their common name. The males have a little extension in the center of their caudal fin. This is an easy way to distinguish them from the females. Also, the boys have blue eyes, and the girls have green eyes. I just wish all fish could be sexed this easily! I mainly feed my colony live baby brine shrimp. I also recommend commercially available freeze-dried and frozen cyclops (e.g. CYCLOP-EEZE) and chopped frozen bloodworms. They will also feed on a variety of high-quality flake food if it's crumbled small enough for their tiny mouths. They also relish daphnia and mosquito larvae, so I provide those when I'm harvesting them, but it is not necessary for their breeding success. A 2-inch thick mat of Java moss that covers the back two-thirds of a bare 10-gallon tank is all that I need to ensure a plentiful supply of fry. The heavy clump of Java moss is not only the breeding area for the adults, but also the hiding place and feeding area for the fry. Clumps of Java moss contain a lot of rotifers, which make a wonderful fry food. Even though the small fry of these fish could be eaten by the parents, it seems that once they get a bit bigger than a baby brine shrimp, the adults leave them alone. You will find that this type of setup will eventually become self-regulating. Once you get about 25 adults in a tank of this size, it will no longer produce any fry. I'm guessing that either the juveniles or the other parents end up picking off the fry. Sell or trade off a few pairs of your extras, and soon you'll have your colony breeding again. When you are performing water changes on these tanks, avoid siphoning out the tiny fry. If you move the moss and see a lot of tiny fry darting away, wait a week until they are a tad bigger and can easily escape the siphon. I also make it a point to check the bottom of the bucket before I dispose of any waste water from their tanks to avoid losing any fry.
 
The second emperor type available is the black emperor (Nematobrycon amphiloxus). There is a color sport now available in which almost the entire fish is a rich velvety black. The males have blue eyes, and the females have green eyes. Some have claimed that this species is tougher to spawn, but I have found them to be quite easy using the "lazy man's method."

The third Emperor type is named after a gentleman who is indeed "The Emperor of Small Fishes," Rosario LaCorte. Rosario is probably the best fish breeder in the United States today. It was after a pilgrimage to New Jersey to see his fish room that I decided to start keeping the emperors. I use five of my tanks and soon to be a sixth tank for the black emperor sport, in efforts to keep and raise these beautiful small fish. The rainbow emperor (Nematobrycon lacortei), also called the red-eyed or LaCorte's emperor, is also an easy emperor to keep and breed. The males have red eyes, and the females have bluish-green eyes.

Keep all three mentioned Nematobrycon in separate tanks so that you don't produce any crosses. I don't know for sure whether they will cross, but so many wonderful rainbowfish and cichlids are being ruined by careless crosses.

There is another tetra called the blue emperor (Inpaichthys kerri).  Even though it is in another genera, we'll give the fish namers a little latitude. They are much smaller than the Nematobrycons, rarely reaching 1 1/2 inches in length. They can be kept in exactly the same manner as the others. There is also a red emperor tetra (Inpaichthys sp.).These are reported to spawn as easily as the others in the group, but I have not figured out how to keep them happy. Until I figure out their spawning cues, they will remain one of the challenging fishes in my fish room.

I hope that I've piqued your interest in working with the emperors. You might find them at a quality local pet shop but also check out your local aquarium club, as they are a favorite and will often show up at the monthly meetings or auctions.