Fish deaths

Hi all,

Not sure if this counts as an emergency but....

Over a period of quite a few months now I have lost a number of my fish, all seemingly going in a similar way. They seem to lose weight and get quite skinny over the course of a week or so, after a while seem to struggle with their swimming, then die over night. Have tested the water numerous times, it's always with acceptable parameters. Changed 10% of the water weekly, and a couple of weeks ago did a 70% water change. Doesn't seem to have made a difference. The latest fish I reckon is getting ill is one of my two remaining giant danios. Attached are photos of a healthy one and another one which is the same length, but has lost weight.

Have previously treated the tank with esha 2000 (79001) and am halfway through a treatment of interpret antibac - to be honest they were medicines I had at home so thought worth a try! I haven't bought any fish for a while now, it doesn't seem right.

Any advice appreciated

Thanks

What are the actual numbers for each parameter you test? POST THE NUMBERS!

A 10% water change is very small 30 to 50% once a week is probably what you need to do. It may take fish several week to recover from bad water from insufficient water changes. So one 70% water change may not work.

StevenF said:

What are the actual numbers for each parameter you test? POST THE NUMBERS!

A 10% water change is very small 30 to 50% once a week is probably what you need to do. It may take fish several week to recover from bad water from insufficient water changes. So one 70% water change may not work.

Click to expand...

DON'T SHOUT

PH 7.2
Ammonia 0
Nitrate 5
Nitrite 0

What does their poop look like?

If fish lose weight over a week or two but continue to eat a moderate (but not normal) amount and then die, they have an internal protozoan infection.

The following link has info on treating fish for internal bacterial and protozoan infections and intestinal worms. Section 2 covers internal protozoan infections.