scotty435 wrote:
I think it's probably a combination of stress and nitrites. The outside tank is a bit cooler as well.
Increase the aeration for the outside fish if possible. It may be too late to save them if the damage is already done but I've seen where Tilapia can make it through some pretty bad spikes. The salt should also help and I would also stop feeding and make certain there aren't any dead fish you've missed.
Here are a few possibilities
1. Low oxygen
2. Ammonia
3. Nitrites
4. pH fluctuations due to algae
5. Toxins (like from leaves or galvanized roofing)
Have a look at see which apply
I totally agree with you. Checking the water quality is another main factor that you should concentrate on. The water should not be chlorinated. You'll have to dechlorinate the water in that case. But I'm not sure about the galvanized roofing. I have read
articles saying that galvanized pipes are dangerous as they accumulate lead into the tap water causing health issues for children and pregnant ladies. I'm not sure whether the galvanized roofing can cause threat.
Fish food is another factor. If fish solids are allowed to accumulate in the system, the ammonia concentration in the pool will increase causing ill health amongst your fish. To prevent this you can try plumbing an offtake from the main pump line that feeds back into the top of the tank to ensure good water circulation around the tank.
Backyard Aquaponics
