Well since yesterday (just my luck so not surprised lol) but my female Betta had been getting through the mesh some how... So that quick fix needs re doing. I'm starting to become very stressed about these fish! Went to check them yesterday and she was on his side. I put her back, watched for a bit, then left them alone. Came back hour later, she was back on his side... I don't know if kids would be this stressful lol!