After 24 h infected fish were checked for infection and transferred to 200 l glass aquaria where they were kept for 8 weeks.
Over the last decade or so, the demand for aquatic plants has strongly increased in order to supply private aquariums, garden tanks or botanical gardens.
Six of these infection aquaria were used, each containing 175- 445 parasites and 12-26 recipients.
The aquaria were covered with dark cloth and placed in dark temperature controlled rooms to reduce irrelevant and stressful stimuli.
The remaining unexposed sibs were maintained in two 100 l aquaria in the same room.
Separate experimental aquaria were used to allow collection of fish in complete darkness without disrupting other animals.
After io injection, goldfish were returned to their home aquaria to recover.
One dytiscid species was tested at a time, and 12 aquaria were used in each of the experiments, eight containing a predator and prey and four controls with prey only.
