Abstract

OLIVEIRA, Sarah Ragonha de et al. Tolerance to temperature, pH, ammonia and nitrite in cardinal tetra, Paracheirodon axelrodi, an amazonian ornamental fish. Acta Amaz. [online]. 2008, vol.38, n.4, pp. 773-779. ISSN 0044-5967.  http://dx.doi.org/10.1590/S0044-59672008000400023.

Poor water quality condition has been pointed out as one of the major causes for the high mortality of ornamental fishes exported from the state of Amazonas, Brazil. The purpose of the current study was to define water quality standards for cardinal tetra (Paracheirodon axelrodi), by establishing the lower and higher for lethal temperature (LT₅₀), lethal concentration (LC₅₀) for total ammonia and nitrite and LC₅₀ for acid and alkaline pH. According to the findings, cardinal tetra is rather tolerant to high temperature (33.3 ^oC), to a wide pH range (acid pH=2.9 and alkaline pH=8.8) and to high total ammonia concentration (23.7 mg/L). However, temperatures below 19.6 ^oC and nitrite concentrations above 1.1 mg/L NO_2- may compromise fish survival especially during long shipment abroad.

Keywords : 96-h LC₅₀; ornamental fish; Paracheirodon axelrodi; water quality.