Classification / Names
Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa
Actinopteri (ray-finned fishes) > Atheriniformes
(Silversides) > Bedotiidae
Etymology: Rheocles: Greek, rheos = stream + Greek, kles, kleis = straits; derhami: Named for Patrick de Rham, director of the Aquatic Conservation Network (Ref. 39832)
Environment: milieu / climate zone / depth range / distribution range
Freshwater; pelagic; depth range - m (Ref. ), usually - m (Ref. ). Tropical; 0°C -
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 5.0 cm SL male/unsexed; (Ref. 39832)
soft rays: 15 - 21;
Vertebrae: 35 - 38. Rheocles derhami is readily distinguished from R. sikorae and R. wrightae by length of upper jaw (32-41%HL versus 46-58) and absence of black pigmentation of genital papilla, from R. pellegrini by number of gill rakers on lower limb of first arch (9-10 versus 6-7), from R. lateralis by caudal peduncle length (67.3-78.6%SL versus 84.6-96.7), and from R. alaotrensis by absence of chest and belly scales and paired predorsal scale rows (Ref. 39832). In life males normally light grey, the second dorsal, anal and caudal fins are bright silvery blue, the throat region is orange-red, light grey females are not brightly colored; preserved specimens are creamy yellow, scale rows in dorsal midline heavily pigmented and darkened (Ref. 39832).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Stiassny, M.L.J. and D.M. Rodriguez, 2001. Rheocles derhami, a new species of freshwater rainbowfish (Atherinomorpha: Bedotiidae) from the Ambomboa River in northeastern Madagascar. Ichthyol. Explor. Freshwat. 12(2):97-104. (Ref. 39832)
IUCN Red List Status (Ref. 124695)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82805
= 0.5078 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01122 (0.00514 - 0.02450), b=3.04 (2.87 - 3.21), in cm total length, based on all LWR estimates for this body shape (Ref. 93245
Trophic level (Ref. 69278
): 3.2 ±0.40 se; based on food items.
Vulnerability (Ref. 59153
): Low vulnerability (10 of 100) .