Fish constantly getting sick

[Sabrina11]

We are suddenly having issues with our fish getting sick. Tank has been set up since nan and suddenly our danio and cherry barbs are just dying off, they get really thin or very bloated, have a curved/deformed spine and then lose the ability to swim. What could be causing this? We do a weekly 30-40% water change and our readings are ammonia 0, nitrite 0, nitrate between 5-10ppm

 

[Pamiam]

It sounds like fish tb, which is a bacterial infection with a very poor recovery rate.

Here is a good article:
Fish Tuberculosis

 

[MICEY]

are you using fresh food , old food will make your fish sick, never use fish food over 6 months old unless you freeze it
always us a quality food and don't over feed

 

[anteatergoanna]

If the tanks been set up for a while, have you looked at " old tank syndrome "?


Sent from anteatergoanna's burrow

 

[PB_Smith]

Do people not read posts before replying???????

It isn't "old food"
and they stated that the tank has been set-up since January (typo I'm sure) so not "old tank syndrome", which would not cause deformities or emaciation.
Old tank syndrome is when you can not get the water parameters to stabilize, especially ph, and only really happens with poor maintenance procedures/habits.

But I agree with the first reply, definitely a disease and not water conditions or food. Given the rapidity and ease of transmission, a bacterial infection is the first to consider.