The role that trace and minor elements play with rainbowfishes and other fishes is related to neurological and metabolic processes (in which these elements play critical roles), as well as overall coloration (trace and minor elements are often at the core of pigments known to enhance coloration); of these aspects, it is coloration that is often most important to the rainbowfish enthusiast, as few experienced hobbyists will deny that male rainbowfish displaying to a female are some of the most brilliantly-colored fishes maintained in captivity. Dosing a trace and minor supplement with every water change performed is an effective method of delivering these substances for maximum benefit. Rainbowfishes and their allies, the Blue-eyes, are native to all manner of water nea and parts of Australia. Water chemistry in these systems varies from moderately-acidic to -alkaline, and extremely-soft to -hard; while it is generally unnecessary to maintain water parameters for a given species exactly like those of their native habitat, it’s sensible to approximate these parameters (e.g. moderately-hard water and alkaline pH for species native to habitats featuring these conditions, and vice versa for fishes hailing from soft-water, acidic waters) for long-term health of the fish. That stated, the majority of rainbowfishes (with few exceptions) adapt well to a general hardness of 9 - 12 dGH (150 - 200 ppm) and pH of 6.5 - 7.5, though some may require harder or softer conditions (Blue-eyes inhabit coastal environments and do well in varying degrees of brackish water; for other species’ requirements, consult a reputable text). Maintaining immeasurable ammonia and nitrite, and <20 ppm nitrate, is more important than attaining specific pH and dGH values for long-term health of rainbowfishes. A number of popular ornamental fish species, such as various gudgeons, gobys and scat are found in the same waters in which rainbowfishes and blue-eyes originate; hence, RainboCode may also be used in aquaria housing these fishes with equal success.