Spots and blotches

Spots, blotches, rings, and ocelli are prominent markings used in the identification of species, especially fishes, and frequently feature in the composition of scientific names of aquatic animals.

These are not rigorously defined terms in ichthyology, different authors appear to have preferences for particular Latin and Greek words leading to a variation in usage.

As a general guide:
Spot – a well-defined circular or sub-circular mark or pigment.
Blotch – an irregular pigment mark, often with poorly defined margins.
Ocellus (plural ocelli) – eye-spot; any spot resembling an eye, usually rounded with a lighter border; often functioning to distract or confuse predators.
Ring – a well-defined circular or sub-circular mark surrounding a feature such as an eye; differing from an ocellus in not resembling an eye.





annul-Latin, anulusa ringPomacanthus annularis (Bloch, 1787), the Bluering angelfish
argusGreek, argos (αργος)mythology, a hundred eyed giant; alluding to spots or dotsCalloplesiops argus Fowler & Bean, 1930, the Finespotted comet
cyclo-Greek, kuklos (κυκλος)ring, circleLabracinus cyclophthalmus (Müller & Troschel, 1849), the Fire-tail devil.
-encaeusGreek, egkeas (εγκεας)burn in, brand; alluding to spotsStegastes diencaeus (Jordan & Rutter, 1897), the Longfin damselfish
-maculaLatina spot, mark, stainCoris caudimacula (Quoy & Gaimard, 1834), the Spottail coris.
-maculatus, -a, -umLatin, maculospot, spotted, variegatedChaetodon quadrimaculatus Gray, 1831, the Fourspot butterflyfish
meleagrisGreek (μελεαγρις)Guinea-fowl; alluding to a spotted patternOstracion meleagris Shaw, 1796, the Whitespotted boxfish
-notatusLatin, nototo mark, designate with a mark, marked, brandCtenochaetus binotatus Randall, 1955,  the Twospot surgeonfish
-ocellatusLatinhaving little eyesSignigobius biocellatus Hoese & Allen, 1977, the Twinspot goby
ocelli-Latin, ocellusa little eye, eyeletChaetodon ocellicaudus Cuvier, 1831, the Spot-tail butterflyfish
pavoLatinPeacock; alluding to a spotted patternIniistius pavo (Valenciennes, 1840), the Peacock wrasse
-pholisGreek, pholis (φολις)scale, spotCephalopholis argus Schneider, 1801, the Peacock hind
-punctatus, -a, -umLatinspotted, dottedArothron nigropunctatus (Bloch & Schneider, 1801), the Blackspotted puffer
Greek, spilos (σπιλος)spot, fleck, blemish; spottedGenicanthus melanospilos (Bleeker, 1857), the Spotbreast angelfish
-stigmaLatina prick, puncture, a mark burned in, a mark of disgrace; spottedSebastapistes cyanostigma (Bleeker, 1856), the Yellowspotted scorpionfish
stigmat-Greek, stigmatias
one who bears tattoo-marks; tattoo-mark, brandEcsenius stigmatura Fowler, 1952, the Tailspot coralblenny