Mbunas dying 1 by 1 everyday? Any ideas?

[Milingu]

kno4te A201 Milingu any ideas?

The eye of the fish looks swollen. This is normally caused by pathogenic bacteria or viruses or kidney failure.
Since nothing else indicates kidney failure I think the fish had an infection.

You can try to treat against bacterial infections and keep the water clean by doing weekly water changes of at least 50%.

 

[Tj203]

Are you checking the carbonate hardness? Maybe you're having swings in PH and it's stress in the fish owl also do you have enough surface movement for gas exchange so they have enough oxygen in the water? I would Definitely add salt you can go to home depot and get the water softener salt they're sold it's $5 for 40 pounds I think instead of $5 for a little bottle at the fish store. Salt is almost always a good idea. Maybe your town switched over from chlorine to chloramines and you need more water conditioning than you needed before? Have you tested it on more than one test kit I've seen API test kids that are bad that are still not expired? Your water conditioner can be bad? Unfortunately there are a lot of variables but the one I Suggested are at least cheap. Good luck

 

[Rocksor]

Is the water in the tank hard? What's the GH reading for the tank/tap?

 

[A201]

The sudden convulsions, leading to a
quick death doesn't sound like a parasitic infestation to me. Maybe an intestinal blockage, which lead to a bacterial infection. Once bacteria damages a vital organ, sudden death can occur. The convulsions were likely a reaction to the resulting extreme pain.
This is just an educated guess. As noted a lot of unknown factors.
Be a good idea to up the weekly WC to 50% & add more varied diet with foods that contain garlic, kelp & othe plant material.

 

[fishdance]

Look up "Old Tank Syndrome"

 

[Deadeye]

Geez, that sounds exactly like what I'm seeing.
Sorry to hear that.

Did you manage to save some in the end of did the whole community succumb to it?

I lost all of mine, as I did not have medicines on hand when it happened.