Hi all,
Irene wrote,
Sorry to hear about your loss, my suspicion would be that it is insufficient oxygen. Aeration and oxygenation are quite complex subjects, and unfortunately the level of oxygen in the tank water is difficult to measure.
Lack of oxygen in the tank water is often a symptom of insufficient biological filtration, leading to a build up of ammonia and or nitrite, you then get a vicious circle of low oxygen levels leading to less efficient biological filtration, which leads to lower oxygen levels, which lead to even less biological filtration and even lower oxygen levels etc.
Have a look here, and see if it might be relevant to your loss: <
http://plecoplanet.com/?page_id=829>
cheers Darrel