Everyone was doing very well and growing. The Zacco's were mating every few weeks. Eggs eaten like caviar.
Event the acrossocheilus, which I believe are also known as "Torrent Carp" in English, were showing signs of courtship. They are super active but really nice fish.
The tanks had reached a nice harmony, except for the Horse Mouths. They get more and more aggressive as they grew to the point that I was considering removing then.







The disaster struck.
I added meds to the whole fishroomto treat for intestinal parasites and worms. During the night the filter outlet was knocked by a fish of moved down just enough to stop breaking the surface of the water and keep it highly oxygenated. Sadly, ALL the fish died.
I came to the conclusion it was suffocation as every other tank was fine. Even the some of the smaller tanks which I dosed slightly higher than prescribed, were fine and I can see the treatment has helped.
This is what I woke up to:

I have cleaned and refilled the tank. The rotting fish, mainly rhinogobius, stuck between the rockwork has slowly been rotting away. This has had a positive effect on the growth of aufwuch/periphyton as this was all but eaten.
I have new plans for the tank. Along the same theme but a little different.
I will keep it as hillstream/fast current tank.
This is one of three tanks I play with and don't try breed something. So I want something more "interesting" to me for now.
This 75g will be a more aggressive flow tank. I have re-added the Sicyopterus Japonicus. I have also added 5 anostomus ternetzi. I will look at slowly restocking with fish that get about 4-5" and like high flow.
The 55g above this will become a paludarium with more passive rheophilic species