Effect of formalin in early stages of the freshwater neotropical catfish, Lophiosilurus alexandri

Toxicity, physiological, histopathological and antiparasitic effects of the formalin, a chemotherapeutic of fish aquaculture

“…The toxic effects of formalin in fish include mortality and are directly proportional to the concentration (Table 1). However, tolerance to formalin varies among fish depending on the species, size (age), treatment conditions (Chmelova et al, 2016; Cruz et al, 2005; Cruz‐Lacierda et al, 2012; Fajer‐Ávila et al, 2003; Hoseini & Nodeh, 2013; Hoseini et al, 2013; Intorre et al, 2007; Neves et al, 2020; Tancredo et al, 2019), among other factors. Therefore, the toxicity of this chemotherapeutic to each fish species must be determined before application, and the data of toxicity and safe ranges of the dose of formalin can be extrapolated for fish farming.…”

“…For Danio rerio larvae, the 144 h‐LC 50 of formalin varied of 0.2 to 4.9 Mn (Meinelt et al, 2005), and for Siganus rivulatus juveniles, the 72 h‐LC 50 of formalin was 551.0 mg/L (Nasser et al, 2017). For Lophiosilurus alexandri larvae with 7 days post‐hatch (ph), the 12 h‐LC 50 of formalin was 108.9 mg/L and for larvae of 45 days was 244.4 mg/L (Neves et al, 2020).…”

Treatments of orange‐spotted grouper (Epinephelus coioides) against Cryptocaryon irritans with •OH, ClO2 or HCHO: Survival, physiological and histological response

“…The fusion and edema of the gill lamellae could compromise oxygen uptake resulting in systemic hypoxia. Several studies also reported that HCHO exposure caused several changes in the gills, such as epithelial detachment, hyperplasia and necrosis in different fish species, which could even lead to the death of fish in severe cases (Neves et al, 2020; Pahor‐Filho et al, 2015; Perera & Pathiratne, 2005). Santos et al (2012) demonstrated that exposure to HCHO at 50 mg/L could be toxic to amazon bluespotted corydora and caused morphological changes (R. F. Santos et al, 2012).…”

“…In contrast, the major alteration in the gill of E. coioides in •OH tank was hyperplasia after 3 days inactivation period. Hyperplasia was a common defence mechanism that reduced the entrance of stress substances by increasing the number of epithelial cells and branchial surfaces (Neves et al, 2020). Liu et al showed that intermittent exposure to the oxidant caused minimal hyperplasia of gill lamellae (Liu et al, 2020).…”