Abstract
The ecology of 20 species of fishes belonging to 10 families has been investigated in a 7.5-acre artificial and perennial lake located on the campus of the Bangladesh Agricultural University, Mymensingh.
The physical environment of the fishes was studied with respect to the size of the habitat, source of water supply, depth of water, transparency of water, seasonal and diel changes in the temperature of air and water, and also the colour of water. The maximum and minimum depths of water in the lake were 261.5 cm and 109.3 cm respectively. The transparency of water showed correlation with the volume of water. No thermal stratification was detected in the lake. The colour of water was grey to brownish green.
The chemical environment of the fishes was studied with respect to seasonal and diel changes in dissolved oxygen, free CO₂, pH and alkalinity of the water, and to pH, phosphorus, nitrogen, calcium and potassium of the bottom soil. The dissolved oxygen content of water was inversely related with temperature. Free CO₂ and dissolved oxygen held an inverse relationship in the water. Direct relationships between pH and total alkalinity, and dissolved oxygen and total alkalinity.