This is fishkeeping.

This morning's water tests were quite surprising. Ammonia, Nitrates, Nitrites, all 0, or too close to call. The pH was 8.6! The Ammonia and nitrites were much higher, so apparently the system has cycled. Yeah. If I can figure out what is killing them, I can add more fish!

I did a 50% water change and noticed the smaller Tilapia hanging at the surface. His eyes were sort of glazed ver and he was rather pathetic looking hanging at the surface. He kept swimming into the outflow from the Flood and drain growbed, and this is a clue, I think.

Cause of death could be...
1. Low Dissolved Oxygen. I don't have a test for this. I added a bubbler to the tank and a fan blowing across the top. Hopefully that is a step in the right direction.
2. Something leaching from the Barrel. - ? Another water change or two may be prudent.
3. Effects of the High pH.
4. Territorial behavior from the other fish I added.

I'm discounting #4 as an option, since another fish looks ill and he was tankmates with the other transfer. Currently the plan is to repeat the high range pH test tonight and see if that is an effect of the Algae or something of that nature. Brenden is going to help me make a PVC spraybar for the growbed Outflow to increase the circulation. We'll also refill the water-change barrel for future use. Finally I WILL get something to block the sunlight from the fishtank tonight.. Even if it is just a cardboard box. The possibility exists that it is a parasite or infection, but I lack the appropriate equipment and supplies to run cultures and stain the slides. Trial and error will have to do.

Here is a quick DIY. Air bubbling out of the end of a hose is better than no aeration, but an airstone is a lot better. More bubbles = More surface area. If you don't have time to run to the store, take a length of Aquarium airhose and block one end with a pebble from the growbeds. Using a thumbtack, punch a number of holes into the airhose. Then zip-tie it to something heavy, connect the aquarium pump, and drop it in the tank. Viola! Instant airstone.