In all the years that I have been keeping fish, I have never seen this before. First I had a Male Tiger Barb that was swimming around the tank erratically, spinning around in circles and darting everywhere. going nose up and just sitting like that for a few seconds and then darting around again and just acting like a fish that's dyeing. I took him out and euthanized him. Weeks later I now have a male Rosy Barb doing the same thing. Does Anyone know what it is?
That is typical of a protozoan infection in the brain. This is usually caused by a dirty tank or filter and lack of water changes.
How often do you do water changes and how much do you change?
Do you gravel clean the substrate when you do a water change?
Do you dechlorinate the new tap water before adding it to the tank?
What sort of filter do you have?
How often and how do you clean the filter?
--------------------
If your nitrates did hit 200ppm+, that could cause it, and it might be an indication you haven't been cleaning the tank regularly, which caused the protozoan infection.
If you are using well water that has nitrates, it could have other chemicals too and these might be poisoning the fish and causing the above symptoms.
--------------------
Wipe the inside of the glass down with a clean fish sponge.
Do a 75% water change and gravel clean the substrate every day for a week. The water changes and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.
Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use them. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens.
Increase surface turbulence/ aeration when using salt or medications because they reduce the dissolved oxygen in the water.
Add some salt, (see directions below).
--------------------
SALT
You can add rock salt (often sold as aquarium salt), sea salt or swimming pool salt to the aquarium at the dose rate of 2 heaped tablespoon per 20 litres of water.
Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, Bettas & gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.
The salt will not affect the beneficial filter bacteria, fish, plants, shrimp or snails.
After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.
When you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.
