How does the European eel see?
The European eel (Anguilla anguilla) is a fish in the order Anguilliformes. Its eyes belong to the vision type Shallow-water fish tetrachromat.
Measured in this species: motion (flicker fusion). One measured dial: a value other than colour or sharpness is measured in this species; colour and sharpness are not measured here. Every value below carries its evidence level and sources; nothing is typed by hand.
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What stands out
- It has one receptor class for colour, so it sees brightness but no hue.
- Its sharpest vision resolves 8.3 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 17 Hz, against 60 Hz for people in this dataset, so fast motion looks choppier to it.[9][11]
- 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 1 receptor class: 498 nm (MWS (green)) ESTIMATE: receptor classes from opsin-gene presence in this species; lambda max per class from the measured class template of the nearest taxon (never from the gene itself) | Group default | [1][2] |
| Sharpness | Acuity 8.3 cycles per degree median of 1 relatives in order Anguilliformes: Avocettina infans | Group default | [3] |
| 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 | [4] |
| Sharp zones (foveas) | Number of foveas 0 group default: mode of tier-A values in vision type V18 within phylum Chordata (2 species: Toxotes jaculatrix, Anableps anableps) | Group default | [5][6] |
| Fovea type ventrotemporal area (high rgc density) | Group default | [5][6] | |
| Night vision | Activity pattern diurnal group default: mode of tier-A values in vision type V18 within phylum Chordata (224 species: Amphiprion ocellaris, Acanthochromis polyacanthus, Acanthurus bahianus, Acanthurus chirurgus, Acanthurus coeruleus… | Group default | [7][8] |
| Rods vs cones cone-dominated | Group default | [7][8] | |
| Motion (flicker fusion) | Flicker fusion frequency 17 Hz median of 2 rows (no bright-light flag) (behavioural/whole-eye ERG rows; all rows: [14.0, 20.0]) | Measured | [9][10] |
Related animals
- Avocet snipe eel same vision type
- Bronze sawtooth eel same vision type
- Laced moray same vision type
- Ribbon moray same vision type
- Slender giant moray same vision type
- Slender snipe eel same vision type
More fish: all fish with measured vision data.
Sources
- Lin JJ, Wang FY, Li WH, Wang TY (2017) The rises and falls of opsin genes in 59 ray-finned fish genomes and their implications for environmental adaptation. Sci Rep 7:15568
- 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
- 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:Schwab et al. 2001
- 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
- Moura et al. 2024. A phylogeny-informed characterisation of global tetrapod traits addresses data gaps and biases. PLoS Biol 22:e3002658. TetrapodTraits v3.0.1.. doi.org/10.5281/zenodo.22536349
- 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
- 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
- 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?