Question

If a freshwater fish is placed in an aquarium containing sea water, will the fish be able to survive? Explain giving reasons.

Answer 1

Conditions required for survival of aquatic organisms:

The quality of water is extremely important for the survival of aquatic organisms which includes the following parameters:

$\bullet$ Chemical composition
$\bullet$ pH
$\bullet$ Salt concentration

The salinity of water determines the ability of an organism to thrive in such an environment.

Adaptation to water:

Freshwater contains a lower salt concentration than seawater. Hence, the freshwater fishes have a hypertonic environment inside than the outer water body. Therefore, they produce urine in large volumes since there is a continuous inflow of water.

If a fish from freshwater is shifted to an aquarium containing seawater (hypertonic medium), it will rapidly start to lose water by exosmosis and become severely dehydrated. Also the freshwater fishes lack an osmoregulatory mechanism to excrete excess salt coming through the sea water and hence, will eventually die.

Final answer

No, freshwater fish will not survive in an aquarium containing sea water