Can swim bladder issues be occasional?
We have an oranda which is behaving strangely. It's in a 100l tank with a half a dozen other fish, water is good, plenty of oxygen, filter working, temperature is correct, plenty of plants to nibble, etc.
It tends to swim near/on the surface and occasionally (periods of up to 20-30 min a few times every day) swims upside town near the top and seems to have difficulty swimming deeper (lower) in the tank. When we inspect again later, it seems to be swimming correctly. We have treated the tank with salt and anti-biotics (seven day course) followed by a 25% water change and are feeding sparingly with bottom of tank feed.
There has been no real change in behavior. The periods of unside down swimming seem to be getting longer and when it behaves in this way, it seems to be in distress. Advice on line is confusing - should we separate it and treat it in a different tank or treat the tank as a whole?
We are thinking of 3 days without food and then feeding cooked pea. All suggestions appreciated.