The fugu puffers, genus
Takifugu
The
Takifugu spp. puffers are important primarily as food fish
rather than aquarium fish, with several being cultured on fish
farms or caught in the cool waters off China, Korea, and Japan to
supply discerning gastronomes with the famous fugu. As is
well known, fugu requires careful preparation, because
some of the internal organs of the fish contain a deadly poison,
tetrodotoxin. Takifugu puffers are also widely studied by
biologists because they have remarkably small genomes, making it
much easier for scientists to study their entire sequence of
genes than is the case with most other vertebrate animals.
Humans, for example, have a genome about seven times larger, and
even that of the humble danio is more than four times larger than
that of Takifugu rubripes.
Most likely as a
by-product of the abundance of these fish in the aquaculture
industry, a handful of Takifugu puffers are now appearing
in aquarium shops with some regularity. The peacock puffer is
particularly common, and being brightly coloured and not too
large, it would seem to have great potential. However, it does
have the reputation for being rather delicate, with many
aquarists considering it impossible to keep alive. At least part
of the problem would seem to be inappropriate water conditions:
these are subtropical fish that normally live in estuaries. They
cannot be kept in freshwater aquaria indefinitely, and they
should only ever be kept in relatively cool aquaria. A water
temperature of 18-20˚C (64-68˚F) is ideal. A higher
temperature reduces the amount of oxygen in the water while
increasing the metabolism of the fish, the result being a fish
that dies from slow asphyxiation.
Besides
temperature, the other big issue with these fish is water
chemistry. All Takifugu live in marine habitats, either in
the open sea or in coastal waters and estuaries. At least two
species are known to spawn in freshwater though, Takifugu
obscurus and Takifugu ocellatus, and as a result these
species are sometimes traded as freshwater fish. While they can
survive in fresh water for months, perhaps longer, both will be
much healthier if kept in at least brackish water. Takifugu
ocellatus should be maintained in brackish water at a
specific gravity of about 1.010-1012, while Takifugu
obscurus can be kept either in similar brackish water
conditions or in normal seawater. Takifugu niphobles is
best considered only a temporary resident of fresh or brackish
water, and needs fully marine conditions to do well over the long
term.
Takifugu
ocellatus is the most widely seen of the two species. It is
easily recognised by its vivid colouration: it has a metallic
green body with bright orange markings on the back between the
pectoral fins and at the base of the anal fin. In terms of
behaviour, this species is unpredictable. It is not a fin-nipper,
at least, but it can be aggressive towards conspecifics. Because
it needs subtropical conditions, standard brackish water fish
from warmer waters do not make ideal tankmates. One exception is
Scatophagus argus, which ranges north into Takifugu
ocellatus territory, and the two might be maintained at
20˚C (68˚F) without problems.
Takifugu
obscurus is a much less attractive fish but is, perhaps, a
better bet for the home aquarium. It has a greyish silver body
with a yellowy band running from the mouth along the flanks to
the base of the tail. Above and slightly behind the pectoral fin
is a large black eyespot ringed with pale grey; the belly is
off-white. Like Takifugu ocellatus, this is a euryhaline
species that lives in the sea but breeds in fresh water.
Juveniles are believed to live in rivers for about a year before
swimming downstream to mature in the open sea. Takifugu
niphobles is a similar species and can be confused with
Takifugu ocellatus, having a similar black patch behind
the pectoral fin. Its body is a much darker grey though, and the
entire upper surface is peppered with small white spots. A giant
among pufferfish, it can reach lengths of up to 80 cm, but even
specimens only half as large will still require massive quarters
with excellent filtration. All in all, not an ideal aquarium
fish, despite the fact that it has proven to be quite hardy and
easy to care for.
This genus of
pufferfish includes a number of small, strictly freshwater
pufferfish from South and South East Asia. Apart from their size,
the most characteristic feature of this genus is pronounced
sexual dimorphism: the makes are usually much more brightly
coloured and invariably posses erectile ridges along the belly
and back. In fact, the scientific name of the genus,
Carinotetraodon, comes from these structures,
karina meaning 'keel' in Greek. When males are
displaying to females, or threatening one another, they raise
these keels, presumably to make themselves look more imposing.
Both sexes can puff themselves up in the normal manner when
alarmed, just like other pufferfish.
Although
Carinotetraodon spp. are territorial and snappy towards
one another, like most other pufferfish, their small size makes
it possible for multiple specimens to be accommodated in a
sufficiently large aquarium. Under such circumstances, males and
females will eventually pair off, and following some fairly rough
courtship behaviour they will spawn, often in a thick mass of
Java moss. The male will then drive off the female and guard the
eggs until they hatch, which normally takes about three days.
Once the fry are free swimming, after another couple of days,
they will accept tiny lived foods, such as microworms, and after
a week or two they can be weaned onto newly hatched brine shrimp
and small Daphnia.
There are three
species of Carinotetraodon regularly traded, of which the
most common is probably Carinotetraodon travancoricus, an
Indian species often simply called the dwarf puffer. It is indeed
a tiny fish, barely 2 cm long when mature, and a densely planted
40-litre (10 gallon) aquarium will comfortably house a single
make and three females without much risk of aggression between
them. Unfortunately, males and females are very similar when
young; so sexing the fish in your retailer's tanks is
difficult. However, once mature, sexing them is quite easy: while
both fish have a dark band along the ventral surface, the
male's is much darker. Males may have stronger overall
colouration as well, particularly when spawning, but this is an
unreliable indicator because there is so much variation in the
colouration of these fish anyway. Besides variation between
specimens, individual fish can also change their colours
depending on their mood.
Carinotetraodon
travancoricus are confirmed fin-nippers, and keeping them
with tankmates such as small tetras or barbs is a bit of a
gamble. On the other hand, they generally get along well with
dwarf suckermouth catfish (Otocinclus spp.) and freshwater
shrimps (Caridina spp.). As far as feeding goes, these
fish are very adaptable, and will take all kinds of live and
frozen foods, including small snails, bloodworms, clean
Tubifex worms, and Daphnia. Brine shrimp are a good
treat and willingly taken, but their nutritional value is low so
they shouldn't be used as a staple. One nice thing about
Carinotetraodon travancoricus is that it is predominantly
day-active, and is in fact remarkably outgoing given its size. It
is also very tolerant of water chemistry, doing equally well in
both slightly soft and acidic conditions and moderately hard and
alkaline ones. As with all pufferfish though, it does not
appreciate rapid changes in pH and hardness, and is very
intolerant of nitrite and ammonium. Provided they are kept in a
well-filtered, mature aquarium, these are lovely fish, and
excellent oddballs for the aquarist with only limited
space.
Less commonly
encountered is the red-eye puffer, Carinotetraodon
lorteti. Found throughout much of South East Asia it has been
known to the hobby for decades, often being traded under an old
name, Carinotetraodon somphongsi. Though well know, its
availability has been patchy, almost certainly because its high
level of aggression and persistent fin nipping make it impossible
to keep in a community tank. In terms of basic
requirements, this species is comparable to the dwarf puffer in
most respects, though being a larger fish it does need a bigger
aquarium. A matched pair may be housed in a 40-litre (10 gallon)
aquarium. Males are easily distinguished from females by their
colours; males are basically brown with mustard yellow stripes
across the head and back. The belly is cream-coloured belly
except for a reddish stripe across the keel running from just
behind the mouth to the base of the anal fin. The tail fin is
greenish-blue and fringed with a thin white band. Females are
attractive but in a different way, sporting a mottled pattern of
light and dark brown above and off-white below. Both sexes sport
red irises, from which comes their common name.
The least widely
seen of the three popular Carinotetraodon species is the
red-tail puffer, Carinotetraodon irrubesco. It is
sometimes muddled up with the red-eye puffer, and females of the
two species are virtually identical, the only obvious difference
being that female Carinotetraodon irrubesco bear thin
brown stripes on the belly that female Carinotetraodon
lorteti lack. Male Carinotetraodon irrubesco can be
immediately recognised by their red tails, but they also have red
dorsal fins and the lighter bands on the dorsal surface are tan
coloured rather than yellow. While it is a toss-up which of the
two species is the more attractive, Carinotetraodon
irrubesco definitely has the advantage as far as personality
goes. It is relatively peaceful and can be kept with a variety of
other fish, provided slow moving species with long fins are
avoided. My own species seem to get along well with cardinal
tetras, gobies, Otocinclus, and juvenile
halfbeaks.
Two additional
species of Carinotetraodon are traded very occasionally, the
Borneo red-eye puffer, Carinotetraodon borneensis, and the
banded red-eye puffer, Carinotetraodon salivator. Male
Borneo red-eyes are similar to C. lorteti but the with
greenish-yellow banding instead of bright yellow and they also
have a distinctive blue tail. Female Borneo red-eye puffers are
essentially identical to female C. lorteti, though the
colour banding on the back may be a trifle more yellowy. Banded
(or striped) red-eye puffers are easy to recognise because of the
vertical banding on the head and body. These bands vary in
intensity, being most obvious on spawning males, but even on
quiescent males should be apparent. Female striped red-eye
puffers look a lot like female Carinotetraodon irrubesco.
Unfortunately, males of these two species are extremely
aggressive, both towards females and other fishes in the
aquarium. Aquarists intent on spawning these fish, should they be
lucky enough to obtain them, will almost certainly need to
condition the female apart from the male, and only introduce the
male when she is carrying eggs. Even then, there are no
guarantees that they will spawn, and separating the fish if
things turn nasty will be essential.
|
%20MD.jpg)
%20MD.JPG)
%20MD.JPG)
%20MD.JPG)
.JPG)
