Microcharacidium is a genus of minute characins from Amazonian South America, found in Brazil, Peru, Venezuela, Colombia, French Guiana, and Suriname. The atlas covers 5 species, among the smallest characiforms known, ranging from roughly 0.5–1 in as adults, including Microcharacidium bombioides, Microcharacidium eleotrioides, Microcharacidium geryi, Microcharacidium gnomus, and Microcharacidium weitzmani. The name eleotrioides nods to the sleeper gobies (family Eleotridae), reflecting a body shape and bottom-dwelling habit unusual for a tetra-like fish; species in this genus are typically found resting on or near the substrate in shallow forest streams rather than swimming in open midwater shoals.
Microcharacidium is essentially unknown in the aquarium trade, its tiny adult size and specialized micro-habitat in leaf litter and slow forest-stream margins keeping it firmly in the domain of ichthyological fieldwork rather than fishkeeping. The atlas lists four species as Least Concern and one Not Evaluated, suggesting no acute conservation crisis has been documented, though as with many small-bodied, narrowly distributed Amazonian fishes, population-level data are genuinely sparse.
Fish of this size and habit likely rely heavily on leaf-litter invertebrates and fine organic material for food, a common strategy among South America's smaller benthic and near-benthic characins, though detailed diet and life-history data specific to Microcharacidium are limited.