Gouramis for the Community Aquarium
In the first part of our look at gouramis, a professional aquarist offers some basic gourami care advice and recommends some of the best dwarf gourami species for your setup.
Without a doubt, gouramis are remarkable fish. Belonging to the family Osphronemidae, which includes the Betta and Macropodus (paradisefish) genera among others, the numerous gourami species we associate with the common name are defined by the engaging presence of little under the head, which are actually modified pectoral fins. These fins wave about in a delicate and sometimes comical fashion as the fish patrols the tank. While the fish is, in fact, using these appendages for sensing its environment, this captivating feature makes gouramis popular in the hobby. And luckily, there are a great many ornamental varieties to choose from, suiting every tank size and experience level.
Gouramis in the Wild
All members of the gourami family have evolved to fill slow moving and heavily vegetated freshwater niches across Asia, from Pakistan and India, throughout the Mekong delta in South Asia and down to Indonesia, and upwards into Southern China and through to Korea. This means they are best suited to an environment similar to that preferred by most soft water tropical forest dwellers we commonly keep (such as those hailing from the Amazon and African rainforests), and while some are very adaptable in terms of water chemistry, others require more acidic, blackwater conditions and advanced care.
Waters for most gourami species are also low in dissolved oxygen, and this is a result of a combination of warm temperatures, low levels of water movement, high turbidity, and the generally high density of aquatic plant matter constantly respiring. These deoxygenated habitats have given rise to the evolution of the labyrinth organ, which is a key characteristic of the Osphronemidae family. The labyrinth organ is a highly folded and vascularized area behind the gills that acts like a primitive lung. When the fish takes breaths from the surface, this organ allows atmospheric oxygen to be absorbed into the bloodstream to supplement normal gill respiration gouramis can be seen performing this breathing behavior regularly in aquariums. In fact, gouramis must have access to humid air above the waterline to survive and will eventually drown without it, so they must not be kept in tanks where they cannot reach the surface.
In the Aquarium
Despite their need for surface air and ability to tolerate low oxygen, gouramis still use their gills, so their aquarium water must be kept clean and well oxygenated if they are to do well. Plants are also essential in any gourami tank in my opinion, ideally real, though silk is a fine alternative. Driftwood and/or rocks can also be added for a natural hardscape, which will create more territories and complete the look. To truly thrive, these fish must have soft cover to explore, nest, rest, and retreat into, and as they are adapted perfectly for this lifestyle, they shine against a planted backdrop.
I have come to really enjoy these fish over the years. They have interesting behaviors and often vivid colors, plus they are well suited to planted aquariums and can be perfect tankmates or feature fish in almost any size tank when stocking is well considered and territories are abundant (though certainly some individuals are more peaceful than others).
While most species available are now tank raised and will adapt to most normal, clean, and stable freshwater chemistries suitable for other freshwater tropicals (with soft to moderate hardness), the specifics for each species are beyond the scope of this article and further research is strongly recommended before purchasing is especially true of more rare, demanding, or wild caught species. Mind you, the learning is always half the fun!
Please note that sizes provided are an approximate average for captive fish, and minimum tank sizes are for a single specimen or pair with maybe a few bottom dwellers. Larger quarters will be required for groups or an active community. Finally, if housing a gourami in groups of conspecifics, you should provide a male to female ratio of at least 1:2, under stock the tank, and ensure dense planting and cover is available to create retreats and territories. Though available in several color morphs, from sunset orange to overall light yellow, the true form of this fish is a knockout, particularly if you can entice breeding colors. Males sport a bright sunshine yellow to saffron orange on the body, with a lighter yellow on the dorsal and anal fin, an orange caudal fin, and a deep navy blue throat and chest.
Though the female of the true form can seem a drab gray with a brown horizontal stripe, it worth keeping a few ladies about to encourage displays from the boys. If you not a fan of the understated natural girls, a good choice (if you not interested in breeding a pure line) may be keeping a more brightly colored female from a selectively bred line to keep the men strutting their stuff. Either way, even when they not showing off, colors of healthy fish are intense and serve as bright brush strokes of color in any community, though tankmates should be peaceful, as any boisterous species can easily intimidate this fish.
This peaceful gourami can also be very happy in conspecific groups and will display fun interactions with others. A great choice for planted tank enthusiasts, the bright color of honey gouramis will pop in an amazing fashion against a heavily planted backdrop, and they are graceful and gentle enough to not disturb most carefully manicured aquascapes. Not for the novice, but still reasonably simple to keep, these fish require soft water and an acidic pH of 5 to a maximum of neutral (7) and are reported to occasionally, with some coaxing, accept pellet and flake foods. Do note that these fish have been reported by several as shrimp assassins a micro predator, this is not surprising. When kept in numbers, they have even been said to hunt prey in groups and behave like a pack of sharks at feeding time, with one zeroing in on the prey, snatching a bite, then whisking off while the rest take their turn in the frenzy. This behavior, while I have not witnessed it personally, sounds fascinating and quite unlike many of the more familiar gouramis.
Sparkling gouramis are quite fine nano community fish, though due to their timid nature and small size of 4 cm (1 inches), they must be housed with similar, teeny tiny companions, such as micro sized rasboras, ember tetras, smaller cory cats, scarlet badis, white clouds, otos, etc., and preferably in an aquarium that is well planted and understocked. Though some are said to behave around ornamental shrimp, given their hunting proclivities, I would not trust them with your prized Caridina. hornwort, Riccia, long trailing stem plants, etc.) is strongly recommended, as these fish enjoy diffused light and need to retire when stressed and swim among vegetation to truly display their natural behaviors. Being suited to most local pH and hardness ranges, their adaptability makes up for their lack of coloration. Though their colors are understated, these gouramis are still quite pretty, with two or more attractive chocolate brown bars running laterally down the body and some blue or red flecking of the fins.
They are also quite peaceful with conspecifics and other small or relaxed tankmates, which makes them a great choice for a calm community and a nice subtle choice to accent a planted tank if you require a larger and/or hardier fish to suit your community conditions. They can be kept in a tank as small as 38 liters (10 gallons). The croaking sound, which gives rise to their moniker, is created by the structures in their pectoral fins for it!