Losing tetras

[Country joe]

Another today, I have 2 black skirt tetras that seem to be not affected. I also have red phantom tetras that are okay, as well as my other fish, I had 6 black phantoms I now have 2 left I'm just going to let it ride out, as there is no use treating if I don't know what's causing it. As all water tests are good.

 

[Country joe]

I'm probably grasping at straws, when I look at the tank I think are they getting enough oxygen, but it looks as if they are, but I've put in a fortnight ago 6 panda corys, and noticed the 6 stay together and swim half way up the tank, but not reaching the surface, I've never had them, so I don't know if this is usual behaviour, my 200 litre tank has a Fluval 307 filter and a fluval mini filter running, would I be better changing the 307 for a Fluval 407?

 

[MattW]

I just noticed a build-up of oily film on the surface of the water in those pictures. That can impact gas exchange. I had it on one of my old tanks a few years back and it did affect the ember tetras I had at the time (constant gasping, lack of movement, etc). A simple airstone/sponge filter will fix it. A temporary fix is using some kitchen roll and placing it on the surface which soaks it up.

I use a very small air pump sold on Amazon for my current tanks. I currently have 2 running and they are great for a single sponge filter/airstone.

 

[Country joe]

Thanks my tanks are in a bedroom where I sleep I've tried a couple of different air pumps and the noise would send me bananas, i tried everything wrapping in towels, hanging them from a hook,, sitting them on sponges, nothing worked.

 

[MattW]

Thanks my tanks are in a bedroom where I sleep I've tried a couple of different air pumps and the noise would send me bananas, i tried everything wrapping in towels, hanging them from a hook,, sitting them on sponges, nothing worked.

I have two tanks running air-driven filters in my bedroom as well. I have the pump plugged into a smart plug so I can alter the times it turns on and off. I have them turn off at 23:50 and then turn on at 4:30 am for half an hour to make sure the tank has enough oxygen and then back on at 10:30 am. If you arent 100% sure on smart plugs I would suggest something like this.

You would have your other filters running throughout the day and the air driven one on for 10 hours a day for example. Just make sure you have a non return valve fitted to the air hose just to be sure.

 

[MaloK]

Thanks my tanks are in a bedroom where I sleep I've tried a couple of different air pumps and the noise would send me bananas, i tried everything wrapping in towels, hanging them from a hook,, sitting them on sponges, nothing worked.

Me too, the sound of the motors of air pumps drives me nuts. The bubbles themselves are not a problem (for me), I even find that it's a relaxing white noise.

In my living room, I suspended the pumps in socks in the back of a wardrobe, and ran the air lines to the tanks from there. The clothes hanging in the wardrobe completely mitigates the sound. And it's perfect.