In Oktober 2007 this new species within the genus Kryptolebias was described.

Kryptolebias gracilis from the Mato Grosso River drainage of the Saquarema Lagoon basin, southeastern Brazil, is described. It is similar to K. brasiliensis in morphometric characters and general colour pattern. Both species share at least four colour patterns unique among congeners, supporting a hypothesis of sister group relationship between them: horizontal rows of greenish blue spots and blue bars on the flank, a dark brown stripe on the isthmus, dark brown and white bars on the basal portion of the anal fin in males and horizontal rows of pale golden to pale blue spots on the flank in females. Kryptolebias gracilis differs from K. brasiliensis by having fewer anal-fin rays, fewer scales in the longitudinal series, fewer mandibular neuromasts, a shorter lower jaw and a dark grey spot on the dorsal portion of the pectoral-fin base. The new species also differs from all its congeners in having a small size, with a maximum recorded adult size of 27.6 mm SL.

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 5 to 15 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 to the water you store the eggs in, some acryflavine 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 polpulations from Surinam this can become a major problem for the breeder as many young fishes must be raised 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.

There lifespan can be up to 3 years in captivity.

Remarks :

Max. size 0.0 cm.
Dorsal 00.0,
Anal 00.0,
D/A 0.0,
LL scale count (average) 00.0
Pre- dorsal length to % SL – 00.0 %
Depth to % SL – 00.0 %

Costa,W.J.E.M. 2007. Kryptolebias gracilis n. sp. (Teleostei: Cyprinodontiformes: Rivulidae): a new killifish from the Saquarema Lagoon basin, southeastern Brazil.