Emperor Tetra

Species/genus: Nematobrycon palmeri

Origin: South America: Atrato and San Juan River basins

Temp: 74 – 81 F (23-27C)

Temperament: non-agressive when kept in schools

Adult Size: almost 2 inches (5 cm)

Minimum Tank Size: 10 gallon

Feeding:prefers live or frozen, will eat floating flakes also. They can be slighty aggressive during their “feeding frenzy”

Sexing: The male will have a trident shaped tail (3 points) the middle point is a continuation of the blackline that runs down the side of the body. Females do not have this middle point, and have what most people would consider to be a regular shaped fish tail (kind of U-shaped).

Breeding: Use soft water, lower the PH to 5.0-5.6, filter the water through peat. Do water changes to lower the temperature about 3 degrees, feed live or frozen foods. If you do all that he fish will spawn in a cave filled with Java Moss or a Spawning Mop. You will notice the fish sending tail signals to each other and going through dramatic color change from all white to all purple/black. The female will enter first, then male follows, this keeps repeating for up to 5 hours. All the other tetras will stay on the opposite side of aquarium, and the spawning male becomes VERY aggressive in defending cave. The male will dart around his territory franticly, all the while going through color changes and sending tail signals to other fish to leave the area , warning them that he will attack if they don’t leave. The parents and other fish might eat the weaker babies, but this is not an issue when there is PLENTY of Java Moss for the fry to hid in. Each clutch conatins 50 to 100 eggs, I usually get about 40 that make it to adulthood.


Very color fish, sometimes they will have hints of bright yellow and purple after they reach adulthood. Takes at least 18-24 months to reach full size, but they can spawn after about 6 months. They school the best when they are kept in groups of at least 5 or 6. They usually have extremely bright blue eyes, but they flash a dark red during spawning and sometimes when they are in direct light. They generally prefer a PH of no more than 7, but 5.8-6.2 is ideal. If you have a large enough cave, and a large enough school for proper schooling behavior, the entire school will sleep in the same cave each night. It is pretty fun to watch, one by one they each go into the cave right before lights out (if you use a timer to shut off the lights at the same time each night)