Alternative name Cynodonichthys xi.

Four new rivulid species are described: Rivulus azurescens, Rivulus pivijay, Rivulus ribesrubrum, and Rivulus xi. Rivulus azurescens and R. ribesrubrum belong to the R. elegans species-group. Rivulus pivijay and R. xi are closely related to the R. elegans species-group, but differ by: 1) an unique reticulate brown color pattern on the body (versus a pattern of red longitudinal stripes); 2) males with the caudal-fin without a yellow/orange posterior border (versus males with a yellow/orange posterior border); and 3) the presence of an ocellus (faint or weak in adult males) on the caudal peduncle in both sexes (versus absence of an ocellus in both sexes, except in females of R. magdalenae and R. boehlkei. Huber & Fels 1985. Some notes concerning R. elegans Steindachner, 1880 are included for comparison.

Keeping and breeding is easy but a tight fitting cover on the aquarium is necessary because their ability to jump, even through the smallest opening, is unbelievable.

This species can, if there is enough space for them, be housed in a tank with more than one male and several females. If separated before and brought together again however, they can be very aggressive towards each other and fight to become the dominant fish. The best way to produce numbers of fry is to put a pair or a trio in a small tank of about 10 litres with a small filter in it or with some aeration. On the bottom of the tank place some peat moss or dark gravel and a floating "mop" to give space for laying their eggs. The fish will, if they are fed a rich variety of live food, spawn during their 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 coloured. It is wise to add an anti fungus to the water you store the eggs in, to prevent fungal attacks.

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 males far out number females. For some species this can become a major problem for the breeder, as he has to raise many fry to enable distribution of a few pairs to other hobbyists. Recent personal tests found that lower pH levels during the time of hatching gave a higher percentage of females. To achieve this I used some peat moss that I added to the container with the eggs just before they were ready to hatch. This peat moss also is a good way to prevent eggs from being attacked by fungus.

Their lifespan can be up to 3 years in captivity.

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