Rainbow Shiner - Hydrophlox chrosomus

Rainbow Shiner (Hydrophlox chrosomus)

The Rainbow Shiner, Hydrophlox chrosomus, is a spectacular North American freshwater minnow prized for its electric breeding colours, peaceful shoaling behaviour and suitability for cooler-water aquariums. Still widely sold as Notropis chrosomus, this active species develops shimmering pink, purple, blue and red tones, especially in mature males during the breeding season. It is a superb choice for well-oxygenated planted aquariums, stream-style setups or unheated temperate tanks, provided it is kept in a proper group with clean, stable water.

Common Name:
Rainbow Shiner, Rainbow Dace, Alabama Rainbow Shiner.

Scientific Name (Latin):
Hydrophlox chrosomus
Still widely traded as Notropis chrosomus.

Maximum Size:
Usually around 5–8 cm, with larger specimens occasionally reaching around 8–9 cm.

Water Type:
Freshwater

Origin / Natural Habitat:
Native to the south-eastern United States, especially the Mobile Bay drainage, including the Coosa, Cahaba, Alabama and upper Black Warrior river systems. In the wild, Rainbow Shiners inhabit small clear streams, springs, creeks and river sections with gravelly riffles, pools and sometimes sandy areas. They are associated with clean, flowing, oxygen-rich water.

Water Parameters:
Temperature: 10–22°C
pH Range: 6.5–7.8
Hardness or Salinity: Soft to moderately hard freshwater; adaptable, but best in clean, mineral-stable water with good oxygenation.

Temperament:
Peaceful and social. Rainbow Shiners are active shoaling fish that should be kept with their own kind. They are not aggressive, but their constant movement and cooler-water requirements mean they are best kept with similarly peaceful temperate or cooler-tolerant species rather than warm tropical fish.

Diet:
Omnivorous micro-predator. In nature, Rainbow Shiners feed heavily on small aquatic and terrestrial invertebrates, insects and drifting food items. In the aquarium, offer quality micro pellets, crushed flakes, fine granules, frozen daphnia, cyclops, bloodworm, brineshrimp, mosquito larvae and occasional live foods. A varied diet helps support strong colour and breeding condition.

Minimum Tank Size:
A minimum of 90 litres is recommended for a small group, with 120 litres or more preferred. A longer aquarium with open swimming space, good flow and high oxygen levels is much better than a small tall tank.

Behaviour & Activity:
A lively mid-water shoaling fish that looks best in groups of at least 6, with 10 or more strongly preferred. Males become much more colourful when mature and may show intense red, blue, purple and pink breeding colours. They appreciate open swimming areas, flowing water, rounded stones, plants and shaded cover. They may spawn over gravel or in association with nest-building native minnows in nature.

Aquarium Category:
Community Fish
Suitable for peaceful cooler-water community aquariums with compatible temperate species, small peaceful minnows, hillstream loaches, White Cloud Mountain Minnows, weather-tolerant danios and other calm fish that enjoy similar conditions. Avoid aggressive fish, large predators, fin-nippers, very warm tropical communities and slow species that may be stressed by constant activity.

Special Requirements or Care Notes:
This is not a high-temperature tropical fish. Keep it in an unheated or cooler tropical aquarium with strong filtration, good oxygenation and regular water changes. Avoid prolonged temperatures above the low 20s°C, especially in poorly oxygenated tanks. Provide water movement, open swimming space and a secure lid, as active shiners can jump when startled. Best kept in groups rather than singly or in pairs.

Suitable for:
Intermediate fishkeepers

Availability:
Occasional in trade / Captive-bred where relevant

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.