| Rivulidae (Rivulines), subfamily: Rivulinae |
| 3.23 cm SL (male/unsexed); 3.72 cm SL (female) |
|
pelagic; freshwater; pH range: 5.2 - 5.9 |
| South America: Araguari river drainage, upper rio Paraná basin in Brazil. |
|
Rivulus giarettai differs from all other species of the subgenus Melanorivulus by possessing a unique color pattern on flank in males, in which red pigmentation is arranged to form a vermiculate pattern. It is similar to species endemic to the central Brazilian
plateau in having ventral process of angulo-articular vestigial, first epibranchial curved, and flank intense greenish blue or greenish golden, to purplish blue above anal-fin base in males; it differs from central Brazilian plateau species by a combination of reduction of black pigmentation on head and humeral region in males, 34-36 scales on the longitudinal series, 30-32 caudal-fin rays, 3-4 vomerine teeth, and caudal fin with bars in both sexes. |
| Occurs at the surface, close to amphibious vegetation at stream bank, with clear to slightly turbid water (Ref. 75625). |
|
Least Concern (LC); Date assessed: 07 November 2018 Ref. (130435)
|
| harmless |
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