Alternative name Melanorivulus illuminatus.

This beautiful Rivulus illuminatus was discovered by W.J.E.M. Costa, C.P. Bove and B.B. Costa during a collectingtrip on 16 January 2007. The locality was 23 Kilometer north of Montevidiu, near the road GO-174, upper rio Paraná basin in a swampy floodplain of córrego da Queixada, Rio dos Bois drainage, Estado Goias, Brazil. Pools were interconnected and shallow and clear. pH was 5,85 at time of collecting.

It did belong to the subgenus Rivulus described by Costa 2006a, that include species of Rivulus endemic to the central- and northeastern South America, including the Amazonas, Paraná-Paraguay- Uruguay, Sao Francisco and Parnaiba river basins.

It is distinguished from all other species of the subgenus Rivulus in having six pelvic finrays (vs. seven) and is also distinguished by the unique combinations of other features like the body pattern in males and females.

Keeping and breeding is easy but 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 much 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 3 to 8 eggs.

The eggs should be collected by hand and stored for about 14-20 days in a small container. 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 without any problem. It takes 4 to 5 months to raise them to maturity. Often the number of males is far above the number of females. For some species this can become a major problem for the breeder as he has to raise many young fishes and so become able to distribute a few pairs to other hobbyists. Recent personal tests laerned that lower pH levels during the time of hatching gave a higher percentage of females. To achieve this I use some peat moss that I add to the container with the egss just before they are ready to hatch. This peat moss also is a good way to prevent eggs to become attact by fungusses.

Remarks :

The species is (2010) not widely spread among hobbyists and therefore no exact info about breeding and keeping is available to me in this moment. It is however clear that the species should not be much different in keeping as other Melanorivulus do.

Max. size 29,0 mm.
Dorsal 9-11,
Anal 12-14,
D/A 7-8,
LL scale count 33-35
Pre- dorsal length to % SL – 0.0 %
Depth to % SL – 0.0 %