M. Petala Patria - Department of Biology, Faculty of Mathematics and Natural Science, University of Indonesia, Depok, Indonesia.
S. Prima Amanda - Department of Biology, Faculty of Mathematics and Natural Science, University of Indonesia, Depok, Indonesia.
H. Susanti - Applied Microbiology, Life & Environmental Research Organization, National Research and Innovation Agency (BRIN), Cibinong Science Center, Bogor, Indonesia.
D. Susilaningsih - Applied Microbiology, Life & Environmental Research Organization, National Research and Innovation Agency (BRIN), Cibinong Science Center, Bogor, Indonesia.
T. Taufikurahman - School of Life Science and Technology, Bandung Institute of Technology (ITB), Bandung, Indonesia.

As a fighting fish and ornamental fish, the growth and color brightness of Betta fish (Betta splendens) are critical to be maintained in good conditions. Spirulina Powder (SP) from a blue-green microalga Arthrospira maxima is a nutrient source that can increase the performance of the fish. The research aimed to determine the effect of A. maxima in increasing brightness and growth in Betta fish. The experiment used a completely randomized design consisting of a control and three treatment groups with the addition of ۵, ۱۰, and ۱۵% SP, respectively. The absolute weight, growth rate, and relative growth were assessed to evaluate the growth performance. In addition, the color brightness, blue color relative brightness, and blue chanel ratio were evaluated using image processing software. The results indicated that adding ۱۵% SP significantly increased the growth and color brightness of Beta fish. Meanwhile, the blue-color change in fish is slightly different among all treatments. Based on this research, SP that contained carotenoids is a potential source for enhancing the color brightness of Betta fish.

Blue-green microalga, Fish feeds, Siamese fighting fish.