The cardinal tetra, Paracheirodon axelrodi (Schultz), is the
most important ornamental fish exported from Brazil and
Colombia. During the transport of this species, Amazon fishermen
usually add unmeasured amounts of tetracycline and/
or table salt to the water in an effort to mitigate stress and
mortality. The aim of the present study was to analyze the
effect of salt, the antibiotic tetracycline and the ammonia chelating
agent Amquel in the transport of this species. Cardinal
tetras were submitted to a 24-h boat transport in water
containing either tetracycline hydrochloride (2.5 mg L
1),
Amquel (26.41 mg L
1), tetracycline + table salt
(2.5 mg L
1 + 66.67 mg L
1), or additive-free water (control
treatment). Whole-body cortisol measurements showed that
fish transported with any water additive had lower cortisol
levels compared to control. However, based on ionoregulatory
and water quality parameters, the addition of tetracycline,
Amquel or the combination tetracycline + salt to the water
of transport of cardinal tetras is not recommended when compared
to control. Although Amquel helped stabilize the pH
and diminish total ammonia levels in the transport water, this
compound dramatically increased net Na+ and Cl
uptake,
and therefore compromised cardinal tetra ionoregulation