We recently showed the presence of 7 physiological cone opsins - R1 (575nm), R2 (556nm), G1 (460nm), G3 (480nm), B1 (415nm), B2 (440nm), UV (358nm) - in ERG recordings of larval zebrafish (Danio rerio) retina. Larval ganglion cells (GCs) are generally thought to integrate only 4 cone opsin signals (red, green blue and UV). We address the question as to whether they may integrate 7 cone spectral signals. Here, we examined the 127 possible combinations of 7 cone signals to find the optimal representation, as based on impulse discharge datasets from GC axons in the larval optic nerve. We recorded four varieties of light-response waveform: sustained-ON, transient-ON, ON-OFF, and OFF, based on the time course of mean discharge rates to all stimulus wavelengths combined. Modeling of GC responses revealed each received 1-6 cone opsin signals, with a mean of 3.8 ± 1.3 cone signals/GC. Most onset or offset responses were opponent (ON, 80%; OFF, 100%). The most common cone signals were UV (93%), R2 (50%), G3 (55%), and G1 (60%). 73% of cone opsin signals were excitatory, 27% were inhibitory. UV signals favored excitation, while G3 and B2 signals favored inhibition. R1/R2, G1/G3 and B1/B2 opsin signals were selectively associated along a non-synergistic/opponent axis. Overall, these results suggest that larval zebrafish GC spectral responses are complex and use inputs from the 7 expressed opsins.