Alternative name Laimosemion uakti.

Rivulus uakti is described from Sao Gabriel da Cachoeira, near igarape la, PK 9.4 of the road Sao Gabriel da Cochoeira to Cucuí, upper rio Negro drainage, rio Amazonas basin, Amazonas state, (northern) Brasil at an altitude of only 99 meters.

Costa discovered the species on August 30. 2003 together with S. Lima and L. Silva.

The name choosen is derived from the ancient Tucano mythology and refers to a "being" living on the banks of the upper rio Negro.

The species is distinguished from al other Rivulus species by having a dark gray bar on the upper part of the Caudal finbase in females.

Rivulus uakti is assigned to a subgenus Owiyeye (Costa 2006) but now transferred into the genusstatus Laimosemion a move which is not followed in this site.

Keeping and breeding is not easy and a good cover of the aquarium is necessary because there ability to jump, even true the smallest opening, is unbelievable.

This species can, if there is enough space for them, housed in a tank with more males than one only and several females. If separated before and brought together again however, they can be very agressive to each other and fight to become dominant to others. The best way to have some offspring is to put a pair or an trio in a small tank from 10 liters with a small filter in it or with some airation. On the bottom some peat moss or dark gravel and a floating "mop" to give space for laying there eggs. The fish will, if they become a rich varity of life food, spawn during there whole adult life and produce daily between 2 to 5 eggs.

The eggs should be collected by hand and stored for about 14 days in a small container. Eggs are 1.6 mm and amber colored. It is wise, to add some acryflavine to the water you store the eggs in, to provent fungus coming up. After hatching, the young fry can eat fresh artemia nauplii but it is wise to feed plancton also or add a lot of floating plants so they can find finest food there to. It takes 5 to 6 months to raise them to maturity. There lifespan can be up to 2 years in captivity.

Remarks :

This species was not in the hobby yet and the above is not my personal experience but as most small Rivulus are breeding the same way I believe this species behaviour will not be much different.

Max. size 6.0 cm.
Dorsal 10.7,
Anal 14.7,
D/A 8.5,
LL scale count (average)33.2
Pre- dorsal length to % SL – 72.3 %
Depth to % SL – 23.1 %