Knowledge Base

Problem

A high percentage of zebrafish larvae are undetected during tracking, particularly in tapping experiments, due to camera misalignment or incorrect Arena Settings configuration.

Details

Users observe many undetected animals in EthoVision XT tracking results. The camera may not be centered or focused on the well plate, causing well-plate walls to appear within the arena boundary and interfering with detection. Incorrect arena boundaries can compound the problem. Reported in the context of tapping experiments on new DanioVision chambers.

Solution

1. **Check camera alignment:** Verify that the camera is centered and focused directly on the well plate. If the well-plate walls are visible inside the arena area in the live video, physically adjust the camera position or its settings.
2. **Review Arena Settings:** In EthoVision XT, open Arena Settings and confirm the arena boundary is drawn tightly around the well plate and excludes the plate walls.
3. **Re-draw arenas if necessary:** Delete and re-draw arena zones so they correspond accurately to each well, minimizing background intrusion.
4. **Re-test detection:** Run a short test trial and review the detected vs. undetected animal count. If a high undetected percentage persists after hardware and arena adjustments, check whether an EthoVision XT software update is available (a bug in certain versions has been linked to detection failures — see article on EthoVision software bugs).