Sooner or later you will come across a reason to have to catch a fish that is in your aquarium. This may be because the fish is injured or ill and needs to be put into isolation in a quarantine tank . To remove an aggressor or a fish that is being bullied. To move fish between tanks, to sell or trade a fish, or for any of a number of other reasons.
Fun fact about fish : It is estimated that there may still be over 15,000 fish species that have not yet been identified. There are more species of fish than all the species of amphibians, reptiles, birds and mammals combined