Backyard Aquaponics
A place to discuss aquaponics

These just don't look that bad . Might help to have some pics of your setup and if you have any pics of the fish with their skin ripped off. Any mechanical way this could happen with pumps of certain areas of the tank? Sometimes the slime layer on the fish can look like skin peeling off like this.

Large die offs are pretty common with low Dissolved Oxygen - I see your DO is high enough. Any chance that the aeration kicks out at night? A combination of feeding and no aeration would probably cause the DO to fall pretty fast.

What's your water source?

Hey scotty435,

The tank does not have any pump, just SLO and inlet of the water which flows by gravity from the header tank.

Aeration should be OK as well at night - both airpumps run 24/7, and both of them run from different sources of power - just in case.

Water source is from tap water but goes through 2 filtration, sand and carbon. The filter is 2 months old, I think that shouldn't be the issue. However, I'll just get a chlorine tester today just to rule it out.

The water is beginning to smell bad, a strong fishy smell. Probably due to too many deaths. What's your take - should I change water? My plants are still growing though. No issue there..

I'd probably change at least some of the water, up to about half as long as the water parameters aren't very different. Check for any dead fish that didn't float and keep tabs on the ammonia.

I watched your videos and I think as long as you're running high DO give reducing water movement a try by turning off or reducing the flow on one of the air diaphragms. I think the water movement is higher than it should be. As the fish get larger increase it back up again.

This is just some info on feeding Tilapia that might have something you can use
http://www.ncrac.org/NR/rdonlyres/574B353A-B11F-4DD7-8A87-23E708DE95A0/0/ncrac114.pdf

Hey guys,

Just thought I'd come back here to update.

My fishes have stopped dying. I don't know what else I did, but I took off most of the airstones and only left in a couple. My suspicion is that there is either too much air, or water disturbance from the airstones...

My fishes have not died for the past 2 weeks now, before that, just a couple of small ones.

Thanks again for all your input, much appreciated!