We had 2 Bala Sharks for a year, happy, healthy, and grew quite large in their 150 gallon underpopulated community tank. Regular water changes, cleaning of gravel, etc., all survive happy and healthy each time.
Until this last gravel cleaning and water change. By bedtime, the Balas were gasping at the surface for air. At dawn there was a funeral. All the other fish in the community made it, no problem at all.
Any ideas why they died? : (
My only thought is, they're gills got clogged with debris during the gravel cleaning. But I have no way to know if that's right or not.
Thanks in advance for your input.