Identification of the tolerant capacity to aquatic environment factors (temperature, pH and dissolved oxygen) of Asian bumblebee catfish (Pseudomystus siamensis Regan, 1913)

Asian bumblebee catfish (Pseudomystus siamensis) belongs to Bagridae family and is an economic value ornamental species. However, biological characteristics of this fish species have been rarely reported in the literature. A study to identify tolerant capacity to aquatic environment factors (incipient lethal temperature (ILT) and incipient lethal pH (ILpH) and oxygen threshold) of Asian bumblebee catfish at three developmental stages namely embryo, hatchling and ten-day post hatching (dph) was carried out from July 2018 to January 2019 at the Experimental Farm for Aquaculture of Fisheries Faculty - Nong Lam University in HCM City. The results showed that the incipient upper and lower lethal temperatures (IULT and ILLT) were 32.5oC and 22.3oC for embryos, 36.7oC and 18.7oC for hatchlings, and 38.6oC and 15.9oC for 10 dph fish, respectively. The incipient upper and lower lethal pHs (IULpH and ILLpH) were 10.7 and 4.4 for embryos, 10.2 and 3.7 for hatchlings, and 10.2 and 3.8 for 10 dph fish, respectively. The oxygen thresholds of the catfish at the three stages were 4.7, 1.1 and 1.0 mg O2/L, respectively. The Asian bumblebee catfish at post hatching stages appears to tolerate to unfavorable environmental factors compared to embryonic one. The study results would be an important scientific base for researches on seed production and conservation of the fish in the future.