Chocolate Gourami (Sphaerichthys osphromenoides)
Chocolate Gourami is a labyrinth fish species belonging to the Osphronemidae family. It is native to Malaysia, Sumatra, and Borneo. It inhabits blackwater streams and peat swamps which are covered by high dense vegetation and see very little light. The water in these swamps usually has a dark-brown coloration due to the humic acids and other tannins released by decomposing leaves and other organic materials. These chemicals also make the water acidic and reduce the mineral content making it difficult for plants to grow.
Chocolate Gourami is also found in some clear water habitats where most conditions are similar, except for the dense growth of plants of different genera like Cryptocoryne, Blyxa, Barclaya, Eleocharis, Utricularia, and Lymnophila.
The Chocolate Gourami, as the name implies, has a chocolate brown color body with yellow vertical stripes. It grows up to a maximum size of 6 cm and has an average lifespan of 5-8 years. The males of this species are generally larger and have more developed fins than females. The females may develop a black spot on the caudal fin and have a slightly rounded jaw to facilitate mouth-brooding.
It is a very peaceful and shy fish. It is recommended to keep a group of a minimum of 6 to 8 fish. This fish is slow-moving and does not do well with larger or more boisterous tankmates. Other slow-moving black water species are good tank mates for Chocolate Gouramis. These include Glowlight Rasboras (Trigonopoma pauciperforatum), Giant Pikehead (Luciocephalus pulcher), Nandus nebulosus, Brilliant Rasboras (Rasbora einthovenii), Dwarf Rasbora (Boraras maculatus), Java Combtail (Belontia hasselti), Crescent Betta (Betta imbellis), and the Striped Glass Catfish (Kryptopterus macrocephalus).
pH: 4,0 – 7,6
Hardness: 0,5 – 6,0 dGH
The aquarium must have a minimum size of 10-30 gallons. Chocolate Gourami is very susceptible to bacteria and skin parasites, so water quality must be good. It needs a heavily planted tank without strong water flow to feel comfortable. The water must be very soft and have very little dissolved minerals. Plants like Sessile joy weed (Alternanthera sessilis) and Indian water star (Hygrophila polysperma) thrive well in these water conditions and are excellent additions to the aquarium. This fish requires dim lighting conditions, so the addition of floating plants can also help in diffusing the light.
Proper Tank Conditions:
It is recommended to have a soft, sandy, or gravel substrate with lots of driftwood roots and branches to provide cover. The addition of other structures like ceramic flowerpots or plastic pipes is also preferred by some aquarists. The specimen collected from the wild need slightly lower pH (4.5-6.0), while the ones bred captive are more tolerant to higher pH values (6.0-7.0). Treatment with peat or commercial liquid pH adjustors can be used to keep the pH low.
The substrate can be covered with beech, oak or Ketapang almond leaves to mimic the black water conditions. These leaves release natural chemicals called tannins which are known to prevent bacterial or fungal infections in the fishes. They also contain micro-organisms which serve as a secondary food source to the fish and their fry.
The water should be changed regularly with only 10-15% being replaced each time. Replacing larger proportions of water at a time can be harmful to the fish.
Chocolate Gourami is an omnivore. In nature, it mostly feeds on aquatic crustaceans, small insect larvae, worms, and other micro-organisms. In aquariums, it relies mainly on live or frozen foods. Brine Shrimp, Daphnia, grindal worms, micro worms, mosquito larvae, blood worms, and white worms are suitable to feed Sphaerichthys osphromenoides. While dry commercial foods are accepted by some specimens, feeding them only with dry foods in the long term is not proper for their health. It is better to alternate their diet with both dry foods and live or frozen live foods.
Chocolate Gourami is a mouthbrooder. They should not be kept in a community tank if breeding is desired. The water conditions and temperature must be optimal for breeding to take place. Sexually active males take on a darker, almost greyish patterning; while receptive females intensify in coloration. High-quality live or frozen foods help to get these fishes into breeding conditions, especially the females.
Spawning takes place at the bottom of the tank, where the female lays eggs on the substrate and the male fertilizes them. Following spawning, the female collects the eggs in her mouth and retreats to a secluded place. The incubation period can be anywhere between 7-20 days, following which the female releases plenty of fully formed fry.
The fry resembles adult Chocolate Gourami in appearance and is large enough to immediately feed on live foods like micro worms or freshly hatched brine shrimp. After the fry is released, removing the parents or the fry to a separate tank is significant. Otherwise, the parents may eat the fry.
The presence of warm humid air above the water surface is necessary for the healthy development of labyrinth organs of the young fish. So, the aquarium must have a tight-fitting cover without any air gaps or holes. 10-15% of daily water changes to ensure good quality water is necessary.
Image Source: https://www.greenaqua.hu/