Fish louse or argulus looks
like a small space ship. It can be seen with the naked eye, and swims in the
water just like a remote control toy.
It has a complicated life cycle,
which makes is a problem when treating. You have to destroy all stages of the
life cycle together.
When feeding on fish with their beak like
proboscis, the adult louse injects a poison to help digest tissue. This does
great damage to the fish and in high numbers will be fatal.
mainly a spring problem. In 2005 and 2006 have been very bad years I've had
many ponds and fisheries with this problem.
The main secondary
infection is columnaris and is transported by birds bathing in waterfalls,
un-quarantined fish and pond plants.
When fish are dipped in 3% salt,
the fish louse will leave the fish and can be seen in container.