Description
The Gold Tetra is known from the slower moving portions of rivers and their tributaries, plus coastal creeks and floodplains, where they sometimes enter slightly brackish waters. These fish are actually fairly modest in colour, but in some regions, populations are exposed to a certain type of trematode parasite which induces a cutaneous reaction; the fish excreting guanin as protection, in turn rendering the fish a dazzling metallic colour (hence the common name). This has led to some taxonomic confusion in the past, with the golden coloured tetras initially being described as a new species – H. armstrongi – but now that the skin reaction is well documented, this is now considered a synonym of H. rodwayi. It’s highly likely that the slimmer silver fishes seen in the trade are actually Hyphessobrycon saizi, with rodwayi being deeper bodied and more rarely seen. Tank bred fish do not display the gold or silver colouration, as they are not exposed to the parasite in captivity. Wild imports of metallic fish are available from time to time, and these highly reflective specimens are truly spectacular.
The aquarium for these fish should be well-established and contain soft, acidic water. There should be a sandy substrate and an abundance of driftwood tangles for the fish to explore, along with some dried Indian almond leaves (Terminalia catappa) scattered on top of the sand (these will require periodic replacement). The tannins leached from the wood and leaves should impart a clear, tea-coloured tint to the water, which will not only help to acidify the environment, but will also ensure the fish feel more secure and will bring out their natural colours. Peat added to the aquarium filter will also be very beneficial. Plants are not abundant in the natural habitat of this species, but may make the tank more aesthetically pleasing. Gold Tetras are a peaceful shoaling species that should always be maintained in good sized groups; we would suggest a minimum of 6 specimens, but preferably 10 or more. Tankmates should be small and peaceable and enjoy the same softwater conditions. Other peaceful Hemigrammus or Hyphessobrycon spp. tetras, pencilfish, hatchet fish, dwarf cichlids (Apistogramma sp. and Mikrogeophagus sp.), Corydoras catfish, and smaller Loricariids (suckermouth catfish) make excellent companions. Acclimatisation should be carried out carefully, and be sure to keep up with small regular water changes to keep nitrogenous wastes at a minimum. Filtration should be efficient but water movement not too vigorous.
