Environmental Enrichment with Aquatic Plants: Impact of Choice Environment on Performance of Bettas (Betta splendens)  

INTRODUCTION: Environmental enrichment is a key strategy for promoting the welfare of captive fish by allowing the expression of environmental preferences and natural behaviors. For Betta splendens, a species native to slow-moving, lentic environments with dense vegetation, traditional simplified rearing containers restrict their natural behavioral repertoire. Introducing aquatic plants emerges as a practical alternative to increase structural complexity. METHODOLOGY: The study was conducted in two phases. First, individual preference was evaluated in 10 males and 10 females over five consecutive days using a circular choice tank with four radial compartments: natural plant (Egeria densa), artificial plant, green compartment, and white compartment, plus a neutral central area. In the second phase, 80 females were assigned to 20 tanks across the same four treatments for 56 days to evaluate growth performance (weight gain, feed intake, feed conversion, and survival) and water microbiology (lactic acid bacteria, heterotrophic bacteria, and Vibrio sp.). RESULTS: Both males and females showed a significant preference for compartments containing natural plants over other choices (p < 0.001), with this preference being more pronounced in males (p = 0.0286). High occupancy was also observed in the central area for both sexes, suggesting environmental vigilance and territorial behavior. In the second experiment, environmental enrichments did not influence growth performance parameters or water microbiological counts (p > 0.05). CONCLUSION: Based on the results, male and female Betta splendens showed a clear preference for environments containing natural plants. The use of different types of environmental enrichment did not affect the growth performance of female bettas. Therefore, natural and artificial plants, as well as green-colored environments, can be used as environmental enrichment during breeding without compromising zootechnical performance. Nevertheless, the preference results indicate that natural plants may be more attractive to bettas than artificial plants.