World Aquaculture March 2019

62 MARCH 2019 • WORLD AQUACULTURE • WWW.WA S.ORG environmental conditions (Table 3). In general, gouramis require 30-45 percent protein, 4-9 percent lipids and 30-40 percent carbohydrates in their diets (Table 4). In addition, the diet should contain carotenoids such as astaxanthin, zeaxanthin or lutein for attractive coloration, and binding agents and preservatives to improve the quality and shelf life of the diet. Gouramis also accept a wide range of supplementary manufactured pelleted and granular feeds, including freeze-dried foods available in the domestic ornamental market trade (Fig. 5). Breeding Gouramis become sexually mature in six months and so young fish can be used for breeding purposes. Usually, males are brilliantly colored with a pointed dorsal fin, while females are dull with a rounded or curved dorsal fin. The male has much longer fins than the female. During the breeding season, mature males develop a dark coloration and pointed fins, while females show bulging abdomens. When choosing a breeding pair, care must be taken to select a mature female that is ready to spawn. Otherwise the aggression of males can result in death of the female if she is not ready to breed. Gouramis breed throughout the year, but there is a seasonal peak during the monsoon season from April to August/September on the Indian sub-continent. An aquarium or small plastic tank of 50-80 L capacity, with a water level of up to 25 cm can be used for breeding. Because they are bubble nest builders, the tanks must be provided with one or two pieces of surface vegetation, such as water hyacinth or banana leaves. This helps in providing stability to the bubble nest. TABLE 3. Size of live feed organisms and stages of preferences. Name of the live food Size Stage of uses Important features Infusoria 0.05-0.3 mm Larvae (newly hatched) Tiny and unicellular; ideal for larvae starter food Zooplankton 0.2-3.0 mm Larvae/Fry Rich protein (60-65%) sources for early stage Artemia nauplii 0.4-0.5 mm Larvae/Fry Filter-feeders, can be enriched with PUFA, vitamin C etc. and provided to larvae and fry Beer Worms Up to 1.2 mm Fry/Fingerlings Highly digestibility and very good food after infusoria and rotifer feeding Chironomid larvae 10-20 mm Fry/Fingerlings/Adult Rich in iron and pigments (Blood Worms) (contains haemoglobin) Tubifex Up to 20 mm long Fry/Fingerlings Rich in iron and pigments (Sludge worm) (contains haemoglobin) Earthworms Size varies according to species Adult/Brood stock Rich protein (60-65%) and fats (9-10%) sources FIGURE 4. Chopped tubifex (sludge worms) as feed for larval gouramis. FIGURE 5. Freeze-dried live feeds.