Last week while showing our aquaponics system to an interested party I noticed that the fish seemed quite lethargic. One fish in particular looked quite bad, as he was drifting head-down in the water. The other fish were sitting very still on the bottom of the tank. I glanced at the thermostat display and verified that the water temperature was 65 degrees F. Knowing the water temperature was warm, the next place to look was water chemistry.
I pulled a water sample and ran the standard panel – ammonia, nitrite, and nitrate. Ammonia came back slightly elevated at 0.25 ppm. Nitrites were zero, and nitrates were high but within normal ranges. I was stumped. By this time the fish looked even worse, with two fish drifting head-down and the remaining fish “clamped” and sitting perfectly still on the bottom of the tank. I was in a panic. The on-line search I ran for fish symptoms came up with ammonia poisoning, but with the ammonia so low I knew that couldn’t be it. The fish were clearly in trouble I had no idea what was wrong.
My husband came home later that evening and I hit as he walked in the door with my near panic about the fish. He was as confused and concerned as I was. We decided to retrace our steps and double-check everything. We checked the thermostat display again, checked the water chemistry, and took another look at the fish. No change. Then my husband did something that had in no way occurred to me – he stuck his hand in the water. He is immediate reaction was “Oh my God that waters freezing!” The thermostat was shot and was misreading the water temperature, preventing the water heater from kicking on. There was the problem with our fish – so obvious I had missed it.
I ordered a second thermostat and had it in hand three days later. The fish were cold, but because they are koi they can take temperatures that are quite low (one of the main reasons we use koi). I swapped out the bad thermostat for the new one. The new thermostat immediately dropped the displayed temperature by 10 degrees F. Over the next 24 hours as the temperature rose the fish’s activity and appetite improved. I was much relieved.
So what is the aquaponic/life lesson here? Don’t overlook the obvious – sometimes a simple approach to problem solving will yield the best solution.
Have a life lesson to share? Something that you did nor did not do that in retrospect now seems so obvious? We would love to hear about. Leave a comment below and let the learning begin.