The penguin tetra originally comes from western Brazil and Peru, but nowadays there is practically only captive bred sold. It is a peaceful fish that is best kept in a school of 10 - 20 pieces in a tank from about 60 cm.
They get up to 6 cm and have low demands on the water as long as it is clean and the temperature between 22 and 26 degrees. As a result, they are well suited for for beginner tanks. The difference between males and females can be seen by the fuller bellies of the females. Make sure that the tank is well covered because they are excellent jumpers. In terms of food they eat both dry and (small) live food and have no high demands.