Effect of feeding mosquito larvae on the coloration of Siamese fighting fish (Betta splendens) during grow-out

Coloration is one of the most valued features in aquaculture or ornamental fish, and the Siamese fighting fish (Betta splendens) (Regan 1910) is an excellent model to study coloration. Carotenoids are one of the pigments that express colour in fish. Microalgae synthesize these pigments, which can be transferred through feeding first to mosquito larvae, then to fish when they feed on mosquito larvae. We tested the effect of feeding mosquito larvae on coloration and growth in Siamese fighting fish. Over a 60-day period, 52 individual Siamese fighting fish (32 males and 20 females) were fed with commercial micro pellets (control diet) or mosquito larvae (experimental diet). We expected that fish fed with mosquito larvae would be more colourful and larger than fish fed with commercial micro pellets. Consistent with this prediction, Siamese fighting fish were more colourful when they were fed the mosquito larvae diet than when they were fed a commercial micro pellet diet. We, therefore, recommend the use of mosquito larvae for Siamese fighting fish production. Additionally, since the Siamese fighting fish is an efficient predator of the mosquito larvae, we suggest the use of this live food as a high quality alternative food and a colour bio-capsule with numerous carotenoid pigments.