Hi there. I'm a new member in Shepherdstown, WVa. I am experiencing a suden fish killoff, and I don't understand the problem. I hope that someone will provide me with suggestions about how to sleuth out the cause. This was a complete surprise.
I've been operating a 2 tank, 3 growbed (IBC) system since June. No previous problems. I have been testing the water daily to see the changes in chemistry.
I use a standard drinking water test strip with 15 tests; a Freshwater Master Test Kit from API that tests for PH, Ammonia, Nitrite, and Nitrate; an electronic PH tester and an electronic EC, TDS, and temp meter for comparisons.
All of this is a test and learning experience that I am undertaking as a way to better understand before I fully stock my system. I have complete recirculation of about 400 gallons among all tanks and growbeds; accomplished with 5 pumps. One pump circulates from deep tank to 5 gallon bio-filter.
In the deep tank, I have 3 10" bluegill grown from fingerlings, and in the shallow tank I have fingerlings, minnows, crayfish, snails, small catfish.
All small fish and crayfish started showing stress overnight, and a few of the fingerlings died. The crayfish are listless and climbing to the surface. I can't tell about the bigger fish in deep tank because they're hiding.
The Nitrate has dropped from 10 to 5.0 in several days. The Nitrite has raised from 0 to 0.5 overnight. Ammonia level raised from 0.25 to 0.75 overnight
There was a temperature change (outdoors) from 80 to mid 60's; and a hard rain. Water temperature did no drop considerably.
Yesterday, I introduced a fresh inlet hose in the shallow tank, and all the fish, even the small catish, became agitated, and hovered in the stream from the new hose. Very uncharacteristic for the small catfish to leave the bottom. All the same water; I just added a second return hose from deep tank. Does that mean the Oxygen supply is low?
I will be grateful for any suggestions. Tank you, Bradley Sanders
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