Paedocypris: the smallest fish in the world

6. March 2020

With a length of 7 mm the females of the smallest fish species in the world, Paedocypris progenetica, become sexually mature. And also the two other scientifically described species, P. carbunculus and P. micromegethes, grow only a few mm longer. All species occur in very acidic black waters in Indonesia and Malaysia. The genus name “Paedocypris” means something like “child carp” and wants to suggest that these dwarfs become sexually mature as larvae, because even fully adult Paedocypris show anatomical features that are otherwise only found in fish larvae.

We could finally import these interesting dwarfs in good numbers and condition, after occasional attempts in the years before could not satisfy. The key to success lies in the catching technique. These tiny creatures should not be exposed to the air if possible. If you catch them with a scoop, i.e. always leave them under water, they are by no means sensitive. 

What species we actually have is not entirely certain. Males that are active in mating are crystal red and have a red mark on their head that is used as a blinking light to lure the females to the spawning ground. They spawn in a belly up position, the eggs are attached to the underside of plant leaves. Usually this Paedocypris species is referred to as P. carbunculus, which we neither exclude nor want to confirm with certainty, since we do not know the exact origin, without which a reliable determination is not possible. It is assumed that there are still a number of scientifically undescribed Paedocypris species. 

For our customers: the animals have code 441268 on our stocklist. Please note that we only supply the wholesale trade.

Text & photos: Frank Schäfer