Artificial Insemination of Fancy Livebearers
Matt Hennig (email@example.com)
Courtesy the Free ABC Newsletter available at http://www.aquariumbulletin.com.
Takeshita reports on his fascinating experiences with artificially inseminating
fancy livebearers. Why you ask would someone hand-collect sperm from male
livebearers and place them into a female fish by artificial means? Because this
technique saves a lot of time in developing and fixing desired genetic
characteristics in strains of livebearing fishes.
insemination (AI) is especially useful in obtaining sperm from lyretail and
veiltail males that have very long or deformed gonopodia and are as a result
unable to mate with females. AI is also useful in identifying sterile males that
do not produce sperm - these can then be eliminated early from the breeding
stock. Further, AI is useful if males are sexually non-aggressive and would
otherwise have low mating success. The technique maximises female reproduction
by allowing for increased egg fertilisation, and it enhances production of
hybrid livebearers. Finally, some female livebearers have blocked or very narrow
openings to the ovarian structures. AI manipulation can aid in impregnating such
give you an idea of the equipment required for AI here is a simplified list:
a magnifying set-up (dissecting microscope) - Pasteur pipettes (0.5mm diameter
tips or smaller) - anaesthetic (e.g. 2 drops clove oil per 5 cups tap water;
e.g.1:7000 of 98% 2-phenoxyethanol) - wet soft cloth or paper towel - isotonic
saline solution to hold sperm before pipetting into female - blunt needle -
recovery bucket with filter and aeration in a darkened environment to calm the
here is how the technique works:
the male fish is anaesthetised and wrapped into a soft, wet cloth, it is held in
such a way as to expose the ventral or belly-side of the fish. The gonopodium
(male sex organ) is then carefully moved in a 180 degree arc, back and forth
about 7-10 times. Then, while using one hand/finger holding the gonopodium
facing forward, the moistened thumb and index fingers of the other hand are used
to rub the sides of the fish from behind the head along the sides to the base of
the gonopodium. This stimulates release of the white-coloured milt. The milt is
collected with a pipette and placed in a drop of isotonic saline. The collecting
procedure may be repeated 2-3 times. The male should be allowed to recover in a
well aerated bucket with tank water after about three minutes of handling time.
The female is anaesthetised and held in the same way as the male. Then, the
genital opening, which is just posterior or behind the anal opening is inspected
and cautiously cleared or widened with a blunt needle. Finally, the milt in
isotonic saline is drawn 5 mm (1/4") into the tip of a Pasteur pipette. The
tip is inserted into the female's genital opening and the liquid injected. Avoid
injecting air and repeat the procedure 3-5 times. As with the male, the female
should be returned to a recovery bucket within three minutes from the beginning
Wait to see if female becomes pregnant.
to Glenn Takeshita, AI is not difficult to learn and master. For a complete
account of Glenn Takeshita's methods, take a look at his article.
Glenn Y. Takeshita. Artificial Insemination of Fancy Swords, Variatus, Moons,
and Mollies. In: Tropical Fish Hobbyist, May 2001, p108-116.