In need of a schooling fish to spruce up the middle water layer of your aquarium? Not really into the idea of the regular old neon tetra or harlequin rasbora? Look no further: the emperor tetra is likely exactly what you’re looking for.
Keep reading for everything you need to know about keeping this regal tetra species in your freshwater tank!
| Name (common, scientific) | Emperor tetra, Nematobrycon palmeri |
| Minimum tank size | 40 gallons (long) |
| Minimum group size | 10 |
| Temperature | 73.5-80.5 °F |
| pH | 5.0-7.5 |
| Difficulty level | Easy |
Emperor tetra description & natural habitat
Description
Nematobrycon palmeri, also known as the emperor tetra, is a striking schooling fish that can reach a maximum size of around 1.5”. Although the females are also a joy to look at due to their lively behavior, the larger male emperor tetras really steal the show.
The boys sport yellow fins, jet-black body stripe, and iridescent blue eyes and back. They’re pretty hard to miss, particularly when they’re displaying, flaring their oversized fins, and squabbling over territory.
If you like a simpler color scheme, selectively bred albino emperor tetras do exist.
Did you know? There’s another fish sometimes referred to as the “emperor tetra” (or royal tetra). Very similar in looks, it can be told apart by its more blueish to purple coloration. This is why scientific names are important! The impostor is called Inpaichthys kerri.
Natural habitat
The emperor tetra is naturally found in South America, specifically in western Colombia. It inhabits the Atrato and San Juan river basins in the department of Chocó, where it lives not in the main rivers but mostly the small streams and slow-moving tributaties they feed.
According to a 2012 report, this species likes clear to greenish-tinged waters with gravelly to sandy or muddy bottoms. Plenty of leaf litter and fallen branches are usually present.
Normally, we always discuss the status of a fish or invertebrate on the IUCN Red List here. Is the species threatened, or is the wild population safe? Unfortunately, as of the time of writing, the answer is: we don’t know. Nematobrycon palmeri is listed as Data Deficient.
The IUCN notes that emperor tetras are locally common, but they’re also the most commonly harvested ornamental fish in some parts of their range. However, it’s not clear whether this is a serious threat to their numbers or not. We hope more information becomes available soon!
Emperor tetra aquarium
The emperor tetra is considered pretty hardy, and we’d definitely say it’s suitable for beginning aquarists. Just make sure your aquarium is fully cycled, and don’t forget to keep up with regular maintenance like weekly water changes!
This species requires similar water values to most South American fish. Emperors do best in acidic water with a pH as low as 5.0, although the commercially bred specimens for sale in the aquarium trade can actually handle up to 7.5 without issue. They like their water quite soft.
Like most other small schooling fish, emperor tetras appreciate plenty of cover in their tanks; it helps them feel safe. They probably wouldn’t encounter many aquatic plants in the wild, but we still encourage their use in the aquarium, particularly floating plants.
You can finish off your aquascape with branches and driftwood, plus a good helping of leaf litter on the bottom of the tank.
Tankmates
The emperor tetra is a peaceful species that will go well with other calm fish in a community aquarium. It’ll get along just fine with peaceful bottom dwellers like Corydoras catfish or Pangio loaches, as well as fellow schooling fish like other tetras or rasboras.
Gourami and dwarf cichlids like Apistogramma agassizii will also work, as the emperor tetra is large enough to avoid being harassed or eaten. That being said, anything significantly bigger should be avoided, lest these beautiful tetras end up as dinner.
Keep in mind that emperor tetras are schooling fish that rely on the concept of safety in numbers in order to feel comfortable. A solo tetra is an unhappy tetra, and it won’t be much fun to look at due to loss of color and activity. It might even become more vulnerable to disease as a result of the stress!
To keep things lively and fun, get a group of at least 10 emperor tetras (more females than males). That’s a minimum; more is better, and a very large group makes for an amazing display. The males may squabble over territory and mates, but real problems are rare.
Emperor tetra diet
Like other tetras, this species is a micropredator that feeds on small invertebrates in the wild. Luckily it takes dried foods in the aquarium, so any sufficiently high-quality small commercial pellet or flake food for carnivores works just fine.
Do keep in mind that variety is the key to a healthy fish, especially for those species that would normally consume live foods. Try switching things up regularly by feeding different (thawed) frozen foods, or even consider maintaining your own live food colony.
All your fish, not just the emperor tetra, will be thankful! Daphnia, brine shrimp, and blackworms are easy starter options.
Breeding emperor tetras
Getting your emperor tetras to reproduce is actually pretty easy, and they make a fine breeding project for the beginning aquarist. In fact, they’ll often breed without any interference on your part if they’re healthy and well-fed. In heavily planted tanks, it’s not unusual for some of the fry to survive into adulthood without being eaten by the adults.
If you would like a higher survival rate, you can set up a separate breeding tank. There are a few different ways to go about this, but here’s what works well for us:
- Use a 10-gallon tank or food-safe tub filled with some Java moss or spawning mops.
- Add a sponge filter and ensure the water parameters are suitable for emperor tetras.
- Make sure your emperor tetras are healthy and fat with nutritious live foods.
- Pick the roundest female and most colorful, active male and move both to the spawning tank.
- If all is well, the pair will likely have spawned by the next morning. Move them back to their normal home so they can’t eat their eggs.
- The eggs will hatch in up to two days, and the fry will finish their yolk sacs in up to 5. At this point, you can start feeding them infusoria or powdered fry foods.
- Once they’re large enough, you can switch the fry to baby brine shrimp.
Don’t be discouraged if the first batch doesn’t work out, learning to breed fish is a process! You can even try different techniques, such as group spawning (using multiple pairs at the same time). Keep a close eye on the water quality.
Conclusion
A beautiful South American biotope aquarium with a striking school of emperor tetras is an absolute treasure for the home or office. Colorful, sparkling fish, happy plants, beautiful driftwood—what more could you wish for?
If you don’t feel like you have the time, energy and knowledge to set up and/or maintain your emperor tetra aquarium, we can help. We’re here for aquarists all they way from design to maintenance, so contact us if you just want to sit back and enjoy!
Sources & further reading
Maldonado‐Ocampo, J. A., Usma Oviedo, J. S., Villa-Navarro, F. A., Ortega-Lara, A., Prada-Pedreros, S., Jiménez, L. F., … & Sánchez Garcés, G. C. (2012). Peces dulceacuícolas del Chocó biogeográfico de Colombia.
