The official journal of The Sri Lanka Veterinary Association
ORNAMENTAL FISH REARING IN SRI LANKA: SOME ASPECTS OF BREEDING OF THE WILD AND NEON STRAINS OF GUPPY (POECILLIA RETICULATA)
Journal - Sri Lanka Veterinary Journal (volume: 48(2))
Volume - 48(2)
Year - 2001
Page Number - 7
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Short Communication

ORNAMENTAL FISH REARING IN SRI LANKA: SOME ASPECTS OF BREEDING OF THE WILD AND NEON STRAINS OF GUPPY (POECILLIA RETICULATA)

U.L.D. Jayantha, B.V.Sc., Ashoka Dangolla, B.V.Sc., Ph.D and Indira Silva B.V.Sc., Ph.D

Faculty of Veterinary Medicine and Animal Science,

University of Peradeniya, Peradeniya

Thirty neon guppy (Poecilia reticulate) from an aquarium in Kalutara, and thirty wild guppy collected from a drain were reared in two separate tanks.  Their F2 offspring fry were reared in separate tanks from birth (Day 1).  The respective males and females of each strain were reared separately after sexing on Day 21. On Day 60, three pairs of males and females from each strain, were reared separately in six different tanks (3 wild and 3 neon pairs). Males were allowed in these tanks for only seven days.  The females in the six tanks were monitored for 3 successive pregnancies.  The age at maturity of male fish was measured by the development of gonopodium.  The respective F3 offsprings were removed from the tanks when fry were one day old.  In addition, the length of pregnancy in females, the fry size and the male:female ratio in F3 offsprings were also monitored in the two strains.

It was evident that the semen get stored within the female guppy giving rise to successive pregnancies.  The males of the wild strain sexually matured much earlier (between 21-35 days) compared to the males of the neon strain (28-50 days).  The overall mean pregnancy period was shorter in the wild strain (21 days) compared to 30 days in the neon strain.  These findings may be manifestations of the efforts of the wild strain for efficient propagation in an altered environment (drain).  Females of both strains produced a second and a third offspring without the presence of males.  However, the wild variety produced a lesser number of fry (mean fry size of 31) compared to the neon strain (mean fry size of 37).  The early sexual maturity and the shorter pregnancy period of the wild strains may reflect their relatively faster propagation compared to neon strain, despite the relatively smaller fry size per pregnancy.  The male:female ratio of the first offspring in the wild and ornamental strain were 3:1 and 2:1 respectively.  However the ratio was 1:1 in the third offspring in both strains.  This shows that the initial natural selection process favors males over females.  If a method could be invented to produce more males which are colourful and therefore has more demand, compared to females, income generated from guppy farming could be increased.

 S.L.Vet.J. 2001, 48(2A): 7-9

 

Keywords: Guppy, Poecilia reticulate, Ornamental fish, Breeding