Look out for shoals of tiger-striped perch lingering in the sun-warmed shallows of lakes and rivers.
These fish spawn in spring, often near half-submerged branches that serve as a solid surface for their developing eggs and help to shelter the vulnerable fry.
More wildlife stories from around the world
- For 50 years, there have been rumours of these fish climbing waterfalls. Scientists just filmed them doing it for the first time
- This river giant can grow over 1m long, weigh more than 5kg and lay an astonishing 500,000 eggs
- Ghostly footage shows thousands of giant spider crabs crawling all over each other. It's the largest gathering of its kind on Earth
- This “unique and crazy” prehistoric fish is the size of a door. Now thousands are being released into a remote Swedish river
