The tiger barb (Puntius tetrazona) is a freshwater fish ornamental species sought after for its striped pattern, bright coloration, and shoaling behavior. Ornamental fish producers in Florida currently compete with overseas production, thus it is important to address limitations and improve culture techniques to support domestic aquaculture. There is minimal research on the life history and culture protocols of the tiger barb to increase production efficiency. One approach to cutting feed costs is to optimize prey visualization and consumption. Research on visual system ontogeny during the larval stage may provide insight into manipulation of lighting parameters to improve feeding success for tiger barb larvae.
The retinal ontogeny of P. tetrazona was examined using microspectrophotometry (MSP). This technique measures the spectral sensitivity of individual photoreceptor cells and can characterize the visual capacity of the larvae. Analysis of P. tetrazona larvae so far has revealed the presence of one rod pigment and three different cone pigments: an SWS1 (UV), and SWS2 (blue), and an RH2 (green, Figure 1). However, further measurements are needed to confirm these findings.
Following MSP analysis, applied experiments will be conducted with manipulations in light intensity and spectrum. The intensity study will compare survival and growth for five levels of white light (0, 7, 70, 270, 700 lux) from 1 to 20 DPH. Treatments for the spectrum study will be selected from the MSP spectral sensitivity measurements. The experiment will also be conducted from 1 to 20 DPH, with results in larval growth, growth uniformity, and survival. The collected data may help inform culture conditions that would be most conducive for effective prey identification, capture, and ingestion by larval P. tetrazona.