Credits: Biovision-Infonet
Some common fish predators and their control measures
| Predator | Type of fish eaten | Control measure |
| Insects and insect larvae | Juvenile fish and eggs and fish just hatched. | i) Oil emulsion to prevent aerial breathing. ii) Use of fish that feed on insect larvae especially those that have gills and can remain in the bottom. |
| Frogs and toads | Juveniles of tilapia and catfish | i) Fence with frog proof wire mesh. ii) Clear bush around pond. Screen both in and outlets. iii) Use traps. Adult catfish and bass eat frogs. |
| Fish | all types of fish | i) Use screen in the inlets and outlets. ii) Do pond draining periodically |
| Snakes | Destroy larval and juvenil fish | Clear bush around the pond and fence properly, using cacti (crown of thorns). |
| Crocodiles, alligators and large lizards. | All types of fish | Proper fencing and keeping dense bushes cut down. |
| Turtles | Prey on catfish | Fencing around pond with wire mesh, trapping. |
| Birds: Wading birds e.g., Herons and egrets Diving birds. Kingfisher, fish eagle cormorants, pelicans | All types of fish and at all stages especially in shallow waters. Cormorants feed on fish just after the fish are fed- when they are most concentrated. | i)
Proper fencing all round and then above with netting material or manila
ropes/strings on poles with bright colored cloth or metal crossed over
the pond. ii) cover ponds with nets or wire mesh, use flash guns, windmills that revolves and flash brilliantly and bells to scare the birds a way. iii) The birds can also be actively discouraged by destroying their nest. |
| Otters | Prey on large fish at night killing more than they can eat. They burrow and live under the roots of trees near the water. Otters are very clever They can even open latches on gates. | i) Proper fencing around the ponds. ii) The otters can also be trapped using special otter traps set in their passages. iii) Guard by use of trained dogs. iv) Fence the pond half way across and thus provide hiding places for fish. v) In general, measures to combat monkeys are also effective on otters’ meaning both are very difficult to control. |
| Man (theft) | All types of fish. This is also considered among the major predators through which fish are lost. | Extremely difficult to control and is most common in cage culture and other intensive fish farming. Can however be controlled by: i) Employing security personnel ii) Use of trained dogs iii) Hidden obstruction to prevent pond seining. iv) Fence farm and lock securely. v) Burglar alarms or electrified fence |
- If the situation is bad, then trapping or shooting can be used as the last resort in cases of birds and otters but in consultation with the authorities
- Be careful when poisoning: predators, humans and non target animals can be affected.