The photos were taken at about 10am on Tuesday, April 22, at Broadfield Brook Wetlands.
The reader believes the issue has been caused by car oil being ‘dumped'’ in the water and has reported the incident to Crawley Borough Council and the Environment Agency.
They said this happened several times in the past year.
Crawley Borough Council and the Environment Agency have been approached for comment.

1. Crawley
Oil in the water at Broadfield Brook Wetlands Photo: Contributed

2. Crawley
Oil in the water at Broadfield Brook Wetlands Photo: Contributed

3. Crawley
Oil in a pond at Broadfield Brook Wetlands Photo: Contributed

4. Crawley
Oil in a pond at Broadfield Brook Wetlands Photo: Contributed