Posted by Shari Horowitz in Tropical Fish Hobbyist Blog on August 19, 2011 at 11:09 am
by David E. Boruchowitz
One evening recently I was sitting in the family room with a couple of my kids, watching a movie. Before dinner I had changed water in my 450 and left the hose in the tank, having simply closed the nozzle. All of a sudden my son said, “That fish is dying…no, it’s dead!”
One of the arowanas was drifting vertically in the current. And then we saw that practically all the fish in the tank were in severe distress. A quick diagnostic revealed that the hose nozzle was just barely open, putting out a tiny but steady spurt. The water level had slowly risen over several hours, and now water was just starting to drip out of the acrylic tank’s top access holes. A quirk of my house’s plumbing is that when I leave a drizzle coming out of the hose, it is hot, even though the full stream is 80°F. So, the tank was very warm, about 90° or more, and the surface was flush against the plastic top, leaving no air-water interface. Those two facts resulted in rapid and extreme oxygen deprivation.
I quickly got to work while my daughter starting wiping up the overflow on the floor. I opened the drain valve and dropped the water level about 8 inches, low enough that the return jets were furiously churning the surface. Then I grabbed the arowana. It wasn’t breathing. Neither was the other one. I alternately took one, held open its mouth, and walked it back and forth at the surface, forcing oxygen-rich water over the gills. Soon they started breathing on their own, and the other fish in the tank started to swim more normally.
In 20 minutes the crisis had passed, with no fish losses.
Needless to say, I now do not leave the hose in the tank, whether it’s turned off tightly or not, but this event brought into focus both how precarious the balance in an aquarium can be and how resilient most fishes are. Minutes—perhaps seconds—later, and there would have been a very different outcome, with a total loss a good possibility. Although I’ve seen the same type of thing many times in my decades in the hobby, it was still amazing to see all of these stricken fish bounce back to full health in such a short time. That’s why I resuscitate ALL fish. Rug jerky jumpers, apparent shipping DOAs, battered losers—all fish get a chance in my tanks. Every once in a while a miracle recovery occurs.