I lost 2 female Rams over yesterday. They have been in the tank for about a week
They started to swim at the top and then one died, the other one followed hours later. They were no obvious signs of diesease, just rapid gill movement. However, all the other tank inhabitants do not exhibit this symptom, therefore, it is unlikely to be an oxygen issue. I noticed earlier tonight that one of my male Rams now has rapid gill movement as well but another male Ram is fine.
Anyone any ideas what is going on? I did a 10% water change yesterday. Nitrite and Ammonia are zero, there is some nitrate - about moderate (test kit is dated, results are not that clear). The males have been in the tank for over a month now with no problems, colours are vibrant but one has rapid gill movement.
Thanks.

They started to swim at the top and then one died, the other one followed hours later. They were no obvious signs of diesease, just rapid gill movement. However, all the other tank inhabitants do not exhibit this symptom, therefore, it is unlikely to be an oxygen issue. I noticed earlier tonight that one of my male Rams now has rapid gill movement as well but another male Ram is fine.
Anyone any ideas what is going on? I did a 10% water change yesterday. Nitrite and Ammonia are zero, there is some nitrate - about moderate (test kit is dated, results are not that clear). The males have been in the tank for over a month now with no problems, colours are vibrant but one has rapid gill movement.
Thanks.