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The Blue Gourami
As more and more new species of fish arrive in the shops, and already popular species appear in ever more vivid colour variations, it is easy for the aquarist to forget some of the old favourites, and the reasons why they were so popular. One of these fishes is the blue gourami, Trichogaster trichopterus. This fish is still easily available in the shops, but has lost some of its popularity to the brightly coloured dwarf gourami, Colisa lalia – a smaller fish that may often seem a better choice for the aquariums of today’s space-constrained aquarists. The dwarf gourami is indeed a beautiful fish, but has been highly interbred to achieve the almost luminous colour forms now available, which has had the end result of producing fish that can be extremely shy and delicate. The blue gourami, on the other hand, continues to have the extreme hardiness that made it so popular with earlier aquarists. All anabantids are air breathers, and with this modification have been able to adapt to life in very still, stagnant, almost anoxic waters. This is one of the reasons that so many representatives from this group of fishes achieved popularity before filtration and aeration had been developed to the fine art it is today.
The paradise fish and blue gourami are both labyrinth fishes that were reputed as easy to keep with a bare minimum of technology. Now, with all the gadgets and gizmos at our fingertips, the blue gourami is just as easy to keep today, requiring only a reasonably calm area of water to swim in, a pH between 6 and 8, and a temperature between 22 and 28C. With these adaptable preferences, a blue gourami can be accommodated in most homes without too much upheaval. In their natural waters they inhabit ditches, canals, ponds, swamps, rivers, and lakes in Malaysia, Thailand, Vietnam and Burma. These habitats are naturally thickly grown with vegetation, and in the aquarium the gouramis are seen to their best advantage against a backdrop of some plants, especially tall ones that they can glide through. In the wild they often migrate into flooded areas and flooded forests, especially in the Mekong floodplain, during the rains, and then return to the permanent water bodies as the floodwaters recede.
Although easy to keep, this should not be translated as meaning that the blue gourami is unattractive or boring. To start with, in its natural form this is an attractive fish, which is also sold as the ‘three-spot gourami’. This is a slight misnomer, as one of the spots is in fact the eye – the other two occur midway along the flank and just before the tail. The body has numerous narrow bands, on a general blue theme. The ‘Cosby’ or opaline gourami is a hybrid form in which the spots are smudged out into blotches or absent altogether. Instead the upper half of the fish is a marbled slate blue on a paler background, with the blue fading out towards the fish’s stomach. This fish is sometimes known as Trichogaster trichopterus sumatranus or even just Trichogaster sumatranus. It is, however, the same species as the standard three-spot! Another variant of the fish is the gold gourami. This is similar to the opaline in appearance, but the colour is an orange gold rather than blue. The marbling is still present, but not as distinctive. Yet another variation is occasionally seen under the name of silver or platinum gourami, which is a more or less uniform white-silver colour. With all these variants to choose from, at least one should fit into your preferred colour scheme!
One of the most appealing characteristics of the gouramis for many aquarists is their demeanour and swimming style. The laterally compressed body cuts through the water without any apparent effort, so that the fishes appear to glide. This impression is enhanced by their modified pelvic fins, which have become extremely long and thin. These trail behind them languorously as they swim, adding to the general air of ease. However, the modified fins are not just a trailing decoration, but are sensory organs used by the fish to help it investigate its environment. In one experiment, when blue gouramis were offered a sequence of new, strange, plastic objects of differing shapes and colours, the fish explored them using these long fins. Surprisingly, the fish appeared to indicate a preference for using the left fin to investigate inanimate objects, while either fin was used for animate objects. Perhaps this is an early form of left-handedness! Although in their swimming the fish look extremely placid and laid-back, the males can be very territorial. It is best to keep only one male, although there can be several females (several is better, as it avoids one getting all the males attention, a.k.a. harassment!) The male can be easily identified by his long, pointed dorsal fin. The females have a shorter dorsal that is rounded, and as they become ready to spawn will grow distinctly fatter in the front of the stomach.
As the male enters spawning condition, he begins to build a bubble nest, by sucking in air at the surface and then blowing it through his gills to make mucous-covered, relatively long-lasting bubbles. These pile up until he has a good area of bubbles, at which time he begins to try to entice the female to visit him underneath the nest. If she is unimpressed or not ready to spawn, the male can become aggressive, so a selection of hiding places, and several females to diffuse aggression, should prevent domestic violence getting out of control. Finally, when the female is ready, she joins the male under the nest and they wrap their bodies around one another in a ‘spawning embrace’, falling slowly through the water as they do so. As they eggs are produced they float up from the mating fish into the bubble nest. After the mating, the female remains motionless for a short time, before she is chased off by the male. During this period he uses the time to round up any eggs that have gone astray and spits them into the nest. This entire process is repeated many times until the female has no more eggs left – this could be after several hours and thousands of eggs.
Once the spawning is complete, the female has no further role in the rearing of the family and the male will chase her away if she approaches the nest, along with any other intruders. If the fish are in a spawning tank she can now be removed – in a community there should be sufficient room and hiding places to allow the other inhabitants to get out of the way of the proud father. He will maintain the nest, guard the eggs, and round up any that fall out, returning them to the oxygen-rich safety of the bubbles. Sometimes he will also spit streams of water at this time. About thirty hours later the tiny eggs hatch. If the fry are being reared, the father should now be removed and the miniscule fry fed on infusoria and baby brine shrimp. If the spawning occurs in a community tank, all the fry will be polished up soon after they become free-swimming – they are not big enough to have any realistic expectation of any surviving in a community without intervention. During the third week the labyrinth organ develops, and the fry must have easy access to the water surface, and a humid atmosphere for their first breaths of air.
Of course, the blue gourami makes an excellent aquarium fish even if you don’t intend to breed them. A male is fine on his own, or with a group of females. Two or three males, though, are a bad plan – unless you can keep a large enough group to break down any territorial tendencies and be diffused, then the weakest individuals will be bullied. With an adult size of around four inches, and only a small mouth for its size, the blue gourami is not large enough to eat many small fish, and will be fine with most community inhabitants of a similar size or slightly smaller. The blue gourami can be expected to live around four years, and is an enthusiastic eater of anything offered. Although they are keen insect eaters and will enjoy live food, they also relish flake and other proprietary fish foods. One surprising taste is for hydra, the pests that often manage to colonise aquaria, and a blue gourami is an ideal solution if you become afflicted with these.
All in all, the blue gourami richly deserves the longstanding popularity it has enjoyed in the aquarium hobby, as a fish that is hardy, interesting and attractive. Next time you are looking around for something new and exciting in the shop, why not consider trying an old favourite instead? The blue gourami is unlikely to disappoint you.
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