The
Madagascar Rainbow: Bedotia geayi
by
Birgit McKinnon, CAS
Originally published in The Calquarium Volume 38, Number 7.
Aquarticles
Bedotia geayi is a native of Madagascar where it inhabits
fast-flowing mountain waters. While not as elaborately
colored as many of the rainbows from Australia and New Guinea, it maintains a pleasing
contrast of red, black,
and gold. The male has two black stripes running parallel to the lateral line, one running
from the mouth through
the eye to the beginning of the caudal fin and the other lower on the body running from
the throat to the back of
the anal fin. As well, the caudal fin has a crescent of black circling the outside of the
caudal fin leaving the fin
lobes a bright red. The split dorsal fin and anal fin are beautifully edged in black and
red but the most vibrant
coloration is seen in the back portion of the dorsal fin and in the anal fin which are an
almost iridescent blend of
gold and orange. The female has only the black markings with a small amount of red edging
in the tail.
When I obtained my six fish in the fall of 1995 they were about 25
mm long and just beginning to develop some
red coloration. Initially I thought I had four females and two males but as the fish
matured, it became clear that
there were four males and two females. Not having an empty tank that I could devote to the
Madagascar
rainbows, I put them in a 60-liter tank with six Melanotaenia maccullochi. The
tank was heavily planted with
Cryptocorynes that allowed the fish open space above the plants for swimming. A
sponge filter with heavy air
flow was used for filtration and a green nylon spawning mop held up with a cork was
present, initially for the
spawning activities of the M. maccullochi.
The fish were active and grew rapidly on a diet of brine shrimp,
flake food, and occasionally, white worms. They
are horrible mooches, always coming to the front of the tank begging for food as though
they haven’t eaten in a
week, making it difficult not to overfeed. Water changes of 50% were done about every 10
days as this species
is sensitive to water quality. Standard Calgary tap water with a pH of 7.6 and hardness of
240 ppm suites them
quite well.
When the fish were only about 30 mm total length, I began to find
eggs in the mop. The eggs were quite large for
rainbowfish eggs; about 1.5 mm in diameter in comparison to the M. maccullochi
eggs which were not quite 1
mm in diameter. Unlike Melanotaenia maccullochi or M. boesemani which may deposit
50 to 100 eggs a day
in the mop, the Madagascar rainbows laid only five to ten eggs a day. Presently, the fish
vary from 50 mm to 75
mm in length and the egg production is about the same. I have not seen them picking at the
mop to eat eggs but it
is a possibility, although the reference books claim that they ignore the eggs and fry. I
stopped gathering eggs
after having accumulated about 60 and have never seen fry in the tank and so am reasonably
certain that they do
eat fry. When I check the mop occasionally, there is only one day’s worth of eggs in
the mop indicating that the
eggs are also being eaten.
The eggs were picked from the mop and placed in a margarine
container with fresh tap water. The eggs are very
robust and may be handled without damaging them. Methylene blue was not necessary as very
few eggs were
infertile. Eyes were visible in two to three days and the fry hatched in about nine days.
The fry are very large
compared to most rainbowfish fry and swim at a slightly head-up angle for the first day or
two. The fry are able
to eat brine shrimp nauplii as a first food, which makes then exceptionally easy to raise.
I transferred the fry from
the margarine container to a 20-liter tank equipped with a corner box filter filled with
carbon between two layers
of filter floss. A clump of Java moss was pulled apart to create a loose web and pushed
down so that the upper
third of the tank was available for swimming. The fry grew rapidly on twice daily feedings
of brine shrimp and
when they reached 12 mm in size it was necessary to supplement with flake food, as they
would eat all my brine
shrimp and more! Now, at just under two month of age, the fry are 25 mm total length and
red is beginning to
develop on the caudal fins of the oldest males.
As the fry got bigger and began to outgrow the 20-liter tank, I
decided to put a few in the tank with the adults to
avoid overcrowding. I was surprised when the adults killed two of the fry even though they
were over 1 cm long.
Interestingly, some M. maccullochi fry of the same size that were also introduced
were unmolested. I rescued
the frantic Bedotia fry and transferred all the fry to a 60-liter tank set up
similarly to the 20-liter rearing tank and
all are doing well.
Few fishes from Madagascar are available to hobbyists. Here is a
species that is colorful, active, easy to maintain,
and easy to breed. In fact, I would recommend this fish to a beginning fish breeder for
both the ease of inducing
spawning and the ease of raising the fry. With the status in nature of Bedotia geayi
rated as threatened, we
should all make an effort to keep this fish from slipping away. I assure you that this
species will repay your efforts
with its beauty.
REFERENCES
"All About Tropical Fish," D. McInerny and G. Gerard,
Harrap Limited, London, Fourth Edition 1989.
"Baensch Aquarium Atlas 1," R. Riehl and H. Baensch,
MERGUS-Verlag Hans A. Baensch, 1986.
"Aquarium Fish Breeding," Ines Scheurmann, Barron’s
Educational Series, Inc. 1989.
"The Complete Aquarium Encyclopedia," J. D. Van
Ramshortst (Editor), Elsevier Publishing Projects, 1978.
|