Oditichthys peruanus
ODITICHTHYS PERUANUS (Regan 1903)
Originally published as “Rivulus peruanus” B.K.A. Information pamphlet No.31 January 1968
Natural Habitat: This species inhabits quite fast flowing streams in the vicinity of Perin (Peru) where it is found at high altitudes.
Size and Coloration: Both sexes attain sizes of around two to two and a half inches. Sexing this species can be a problem due to their late maturing and the lack of the caudal base spot in the female.
Male: Ground colour: fawn brown with a light violet sheen in the flanks just above the anal fin. Belly and throat areas are pinkish overlaying these ground colours and numerous salmon pink spots, these spots being more concentrated in the middle flanks. Pectoral fins clear, ventral fins lime green tipped reddish – brown, anal fin yellow with a few salmon pink spots near to the body, the lower edge is finely edged reddish – brown. Dorsal fin very pale yellow, frontal edge stone yellow. Caudal fin near clear with numerous faint pink dashes being more pronounced towards the base, outer edge having a metal silver sheen.
Female: Colour as for the male but to a lesser degree as well as having less red streaks in the caudal. Eyes silver blue.
Care and Maintenance: This species is found to be a slow grower and late maturing. Fry raised in neutral to slightly alkaline water tend to make better growth than fish raised in water with an acid reaction, water with a reading of 7.0-7.2 pH and a DH of 10-12 is ideal for raising and spawning temperature around 72F. – 74F. Fish housed in tanks without aeration tend to be less active than fish kept in water that has movement, this being more in keeping with their natural habitat.
Feeding: Foods in the form of tubifex, white worm, daphnia, mosquito larvae, scraped beef heart and earth worm. In short Rivulus Peruanus is a very greedy eater, size for size I don’t know another species of Rivulus to equal it’s appetite.
Breeding and Rearing: Pairs should be well conditioned and housed in a tank of around 14″ x 8″ x 8″ by using three or four mops some protection is given to the female in so much as she will have somewhere to rest in between spawning. Mops are taken to as well as plants, in fact I have noted that this species takes to mops over plants. These mops are fastened to the sides of their tanks by suckers. This once again is more in keeping with their natural spawning sites, coming from flowing streams these fish would spawn in quieter waters towards the banks, where algae and plant roots would be more abundant. Egg eating can be a problem, if possible, change mops or harvest eggs every day, this helps save eggs from their eager appetite. Eggs take around fourteen days to hatch, eggs placed in lunch boxes often need some form of agitation to help release fry. On hatching fry are large enough to take micro worm and baby brine shrimp as a first food, considering their big appetite fry are not fast growing. As fry grow on they become quite aggressive towards each other, because of this, growing on tanks should be as large as possible so as to allow smaller fry room to escape bullying.
Due to their slow growth rate, late maturing and egg eating tendencies, I’m afraid this species will never be commercially available, which is a pity for in this species we have one of the most colourful Rivulus.
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