Background: With remarkable growth in aquaculture, the need for system diversification and species diversification has been demanded by the producers to gain fruitful output in terms of profit. Striped murrel, Channa striata has been identified as a suitable species for modern aquaculture systems in terms of species diversification due to their fast growth rate, air-breathing nature, higher market price and consumer acceptance. The major bottlenecks in seed production of murrel are captive maturation and short spawning window. To overcome these problems, an attempt was made to achieve early gonadal maturity of striped murrel in captive conditions by intervening in the brooder rearing habitat. Methods: In this regard, four habitats were tested in duplicates, namely T1 - Tank with clean reservoir water without macrophytes and soil base, T2 - Tanks provided with floating (Water hyacinth, Eichhornia sp) and submerged (Waterthyme, Hydrilla sp) aquatic macrophytes without any soil base, T3- Tanks provided with only soil base (15-20 cm) without any macrophytes and T4 - Tanks provided with both soil base and macrophytes. Result: At the end of the three-months rearing phase, the fishes provided with macrophytes and soil base (T4) resulted in early maturation characterized by an egg size of around 1.29±0.21 mm and the majority of late granular stage oocytes and spermatozoa in ovary and testes, respectively. The results concluded that providing a bottom soil base of 15-20 cm and covering the 20-30% water spread area using aquatic macrophytes in the brood rearing tank helped in the gonadal maturation of striped murrel during pre-monsoon in captive conditions.

The experiment was conducted to find out the best rearing system for hybrid tilapia young fry. Rearing of hybrid tilapia young fry (Red strain) was undertaken in two types of rearing systems for 21 days. Young fry of hybrid tilapia (0.12 ± 0.019 g average body weight) was stocked in hapa at a stocking density of 87 fish/lit and in 3 aquarium tanks at a stocking density of 88 fish/lit. Fry were fed with crumble feed having 30% CP @7 times a day in the first week, 6 times in the second week and 5 times in the third week in both hapa and tank. The physico-chemical parameters ofhapa and aquarium tank were taken every day. The DO, pH, TDS, alkalinity and temperature were higher in the hapa than in the tank water. And ammonia was found to be higher (0.5-1 mg/L) in the aquarium tank system. After 21 days of trial, hapa stocked fishes had a weight gain of 3.48 g, while the fishes in aquarium tank had weight gain of 2.58 g. The survival rate in hapa and aquarium was 97% and 85% respectively. The hapa rearing resulted in 74% more growth than in the glass aquarium tank. The final average body weight of fishes reared in hapa was 3.6 g while that of aquarium tanks was 2.7 g. The body colour of the fishes in hapa was brighter than the tank of fishes. To conclude it was found that rearing of red tilapia fry was comparatively better in hapa as compared to glass aquarium.

Fish masculinization in aquaculture refers to a process that involves the development of secondary male sexual characteristics in female fish or the alteration of the normal sexual differentiation process. This term refers to the production of male-typical characteristics. Methods of masculinization typically involve hormonal treatment, natural variation, genetic manipulation, and temperature control. 17α-Methyltestosterone is use for hormonal treatment it is a synthetic derivative of testosterone, which is a male sex hormone (androgen). Use medicinal herbs and plants like papaya seed (Carica papaya) for natural variations. They have active ingredients like caricaine, carpasemine enzyme, and oleanolic glycoside, which has been shown androgenic effect. Genetic manipulation is done by selective breeding or genetic alteration to create fish with male sex chromosomes. For temperature control, the temperature at which eggs are incubated can influence the sex of the offspring. Aromatase inhibitors are also used as masculinization agents. They work by blocking the aromatase enzyme, which turns the hormone androgen into small amounts of estrogen in the body. The benefits of masculinization include its potential to produce monosex populations, reduce the risk of breeding issues, and promote uniform growth. However, challenges such as hormone-related side effects, environmental concerns, and long-term sustainability must be addressed. This study examines the methods and results of fish masculinization procedures in aquaculture, emphasizing their use, advantages, and difficulties for various species. It also makes recommendations for future research directions in the quest for more effective and sustainable aquaculture methods.