How does the Pacific gregory see?
The Pacific gregory (Stegastes fasciolatus) is a fish in the order Perciformes. Its eyes belong to the vision type Shallow-water fish tetrachromat.
Measured in this species: colour and night vision. Measured colour or sharpness: a measured receptor set or acuity in this species; other dials come from relatives or group defaults. Every value below carries its evidence level and sources; nothing is typed by hand.
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What stands out
- It has three colour receptor classes, like most people, but one of them sees ultraviolet.
- Its sharpest vision resolves 3.03 cycles per degree: the finest stripe pattern it can tell apart from grey.
- Both eyes see the same 32.85° in front of it (binocular overlap), where depth is judged best.
- It stops seeing flicker at 89 Hz, against 60 Hz for people in this dataset, so fast motion looks about 1.5 times slower to it.[11][12]
- Activity pattern: diurnal.
The six dials
Evidence levels: how the tiers work. "Measured" means a value measured in this species; "Estimated" values come from a close relative or an eye-size formula.
| Dial | Value | Evidence | Sources |
|---|---|---|---|
| Colour | Colour receptors 3 receptor classes: 363 nm (UVS), 470 nm (SWS (blue)), 528 nm (MWS (green)) measured in this species | Measured | [1][2][3] |
| Ultraviolet yes: at least one receptor peaks in the ultraviolet | Measured | ||
| Sharpness | Acuity 3.03 cycles per degree median of 4 relatives in family Pomacentridae: Dascyllus marginatus, Amblyglyphidodon curacao, Pomacentrus amboinensis, Amphiprion akindynos | Estimated | [4][5][6] |
| Field of view | Binocular overlap 32.85° group default: median of tier-A values in vision type V18 within phylum Chordata (2 species: Danio rerio, Notemigonus crysoleucas) | Group default | [7] |
| Sharp zones (foveas) | Number of foveas 0 mode of species-v1 relatives in order Perciformes: Toxotes jaculatrix | Group default | [8] |
| Fovea type ventrotemporal area (high rgc density) | Group default | [8] | |
| Night vision | Activity pattern diurnal mode of 1 rows (of 1 rows): diurnal | Measured | [9] |
| Rods vs cones cone-dominated nocturnal -> rod-dominated; crepuscular / cathemeral / mixed -> mixed; diurnal -> cone-dominated | Derived | [9] | |
| Motion (flicker fusion) | Flicker fusion frequency 89 Hz median of 1 relatives in family Pomacentridae: Acanthochromis polyacanthus | Estimated | [10] |
Related animals
- Banded archerfish same vision type
- Yellowfin tuna same vision type
- Ambon damelfish same vision type
- American yellow perch same vision type
- Atlantic spadefish same vision type
- Barrier reef anemonefish same vision type
More fish: all fish with measured vision data.
Sources
- Losey GS et al. 2003. Visual biology of Hawaiian coral reef fishes. I. Ocular transmission and visual pigments. Copeia 2003:433-454. doi.org/10.1643/01-053
- Schweikert LE, Fitak RR, Caves EM, Sutton TT, Johnsen S. 2018. Spectral sensitivity in ray-finned fishes: diversity, ecology and shared descent. J Exp Biol 221:jeb189761. Table S1. doi.org/10.1242/jeb.189761
- VPOD in-vivo (MSP / single-cell) lambda max compendium, file scp_cleaned.csv, VPOD GitHub (Frazer et al. 2025 bioRxiv 10.1101/2025.08.22.671864). github.com/VisualPhysiologyDB/visual-physiology-opsin-db/tree/main/scripts_n_notebooks/vpod_ML_workflows/mine_n_match/data_sources/lmax/vpod
- Caves EM, Sutton TT, Johnsen S (2017) Visual acuity in ray-finned fishes correlates with eye size and habitat. J Exp Biol 220:1586-1596. Table S1.. doi.org/10.1242/jeb.151183
- Caves EM, Fernandez-Juricic E, Kelley LA (2024) Ecological and morphological correlates of visual acuity in birds. J Exp Biol 227(2): jeb246063. Supplementary Table S1.. doi.org/10.1242/jeb.246063
- Stieb SM, de Busserolles F, Carleton KL, et al. (2019) A detailed investigation of the visual system and visual ecology of the Barrier Reef anemonefish, Amphiprion akindynos. Sci Rep 9:16459
- Pita D, Moore BA, Tyrrell LP, Fernandez-Juricic E. 2015. Vision in two cyprinid fish: implications for collective behavior. PeerJ 3:e1113.. doi.org/10.7717/peerj.1113
- species_v1:Temple et al. 2010
- Froese R. & Pauly D. (eds). FishBase, snapshot v25.04 (morphmet, morphdat, species, families tables), distributed as parquet by C. Boettiger for rfishbase.. fishbase.org
- Lafitte A, Sordello R, Legrand M, Nicolas V, Obein G, Reyjol Y. 2022. A flashing light may not be that flashy: A systematic review on critical fusion frequencies. PLoS ONE 17(12): e0279718. S10 File (CFF database). doi.org/10.1371/journal.pone.0279718
- Healy K, McNally L, Ruxton GD, Cooper N, Jackson AL. 2013. Metabolic rate and body size are linked with perception of temporal information. Animal Behaviour 86:685-696. Table 1. doi.org/10.1016/j.anbehav.2013.06.018
- Inger R, Bennie J, Davies TW, Gaston KJ. 2014. Potential biological and ecological effects of flickering artificial light. PLoS ONE 9(5): e98631. Table 3. doi.org/10.1371/journal.pone.0098631
Every value cites its sources (all sources). Data: catalogue-v1, built 2026-09-29. Accuracy notes: how accurate is this?