Author: Crampton, de Santana, Waddell & Lovejoy, 2017
Comments: The type series was sampled from the lower, seasonally flooded reaches of low-conductivity blackwater rainforest streams that flow into lago Tefé, and lago Amanã (large blackwater ria lakes of similar conductivity to the streams). Mostly found in marginal root mats or submerged leaf litter along stream edges. The recorded water parameters at the time of sampling were the following: conductivity 10-30 μScm-1, dissolved oxygen 2.0-5.2 mgl-1, temperature 24.3-27.0°C, and pH 4.5-6.0.  During the high water period, this species disappears from the flood-swollen lower stream reaches which is possibly due to declining dissolved oxygen levels, and apparently moves upstream to terra firme stream reaches  above the seasonal river-floodplain flood influence.  Breeds during the early rising-water period, which in the Tefé region corresponds to the rainy season. Occurrence of this species outside the sampling area of type series localities are all recorded from low-conductivity blackwater rainforest streams.  In the region of the type locality, <i>Brachyhypopomus batesi</i> co-exists in geographical sympatry and ecological syntopy with the following species occurring in terra firme stream: <i>B. beebei</i>, <i>B. brevirostris</i>, <i>B. sullivani</i>, and <i>B. walteri</i>. It is also allotropic in distribution with <i>B. belindae</i>, <i>B. bennetti</i>, <i>B. flavipomus</i>, <i>B. hamiltoni</i>, <i>B. hendersoni</i>, <i>B. pinnicaudatus</i>, and <i>B. regani</i>.  In the rio Negro, it occurs in geographical sympatry with <i>B. beebei</i>, <i>B. brevirostris</i>, <i>B. bullocki</i>, <i>B. hendersoni</i>, <i>B. regani</i>, <i>B. sullivani</i>, and <i>B. Walteri</i>.  Feeds on aquatic insect larvae (primarily Chironomidae), and other small aquatic invertebrates (Ref. 116763).