Metallic Topminnow

About

The Metallic Topminnow (Girardinus metallicus) is a small Cuban livebearer with an interesting backstory. It entered the aquarium hobby in the early 1900s, then essentially vanished from the trade, only resurfacing at a Berlin zoo in 1965. Since then it has been maintained by specialist breeders and turns up occasionally in shops. In the wild it inhabits ponds, lakes, and slow-moving or nearly still streams, where it grazes on algae, diatoms, insect larvae, and plant material. That broad diet translates well to captivity, where it will accept most standard foods, though offering some vegetable-based options is worthwhile. Males develop a noticeable metallic sheen along their flanks, which is where the common name comes from. Temperament is peaceful, but water chemistry deserves some thought. This species handles hard, alkaline water and even mildly brackish conditions better than soft, acidic setups. Tankmate selection should reflect whichever approach you take: hardy corydoras and tetras work in hard freshwater, while bumblebee gobies and similar small brackish species make good companions in a brackish arrangement. Breeding follows the typical livebearer pattern and is quite straightforward as long as soft, acidic water is avoided. Males can harass females persistently, so keeping several females per male and providing dense planting helps considerably.