I have collected my sample of Three-spined sticklebacks in the wild, near Öxelösund, Sweden. I have conducted three separate behavioral tests on the fish. 64 fish were used in the study.

In this test, the fish were placed in a new aquarium setup with both a hiding place and visual barriers to keep the fish from perceiving the entire at once. Their initial reaction, interactions with the environment, and exploratory behaviour was observed over the course of 15 minutes

After the first test, a mirror was inserted into the setup so that the fish could see their own mirror image. Their initial reaction and their interaction (or the lack thereof) with their mirror image were recorded over the course of 10 minutes.

After the second test, the fish were startled by thrusting a foreign object into the water rapidly while they were close to the surface. Their reaction to this event and ther subsequent behaviour were observed over the course of 5 minutes.

The test series explained above was conducted on two separate occasions. Once both instances were completed, fish were euthanized and dissected to confirm the presence of parasites and weighed to measure the amount of parasites they were carrying, compared to their full weight.