I had been having some problems with one of my goldfish tanks for a few months. The fish were always getting sick and dying and I was never able to figure out what the problem was, or how best to treat it. I lost quite a large number of goldfish to this problem, but through it all, my Bristlenose Ancistrus type catfish (an algae eater) never seemed to be affected.
I keep these bristlenose catfish in my goldfish tanks, because they
are not as likely to clean
the goldfish as other algae eaters
are. They also stay relatively small; about 5 inches as opposed to the
monster 24 inches I’ve seen standard plecos attain.
While attempting to clean out one of these sick
goldfish tanks, I
forgot to remove the Ancistrus. I drained the tank, cleaned out
the filter, and then filled the tank back up with cold water. This was
in the middle of winter and the water was so cold that condensation
formed on the glass almost immediately, and putting my hand in the
tank for just a few moments caused my fingers to hurt.
A little while after refilling the tank, I noticed the Ancistrus lying motionless on the bottom of the tank. Considering the intense cold and the lack of dechlorinator, I pretty well guessed that the Ancistrus was dead by the time I saw him, but I reached in to the icy water to pull out the remains, and found that he was still alive.
His gill plates were not moving but the spurs next to his gill covers were fully extended, and his body was twitching slightly. This could have simply been the last twitching of the nerves of a dying fish, but I have never been known to give up that easily on one of my fish.
Now, we all know that when working with fish we must be very careful not to stress them. When moving them from one tank to another, we must always attempt to introduce them into their new environment slowly, since the chemistry of the water could be very different. If we take them from one type of water and simply dump them into water of a different chemical make-up, the shock can cause outbreaks of disease or even sudden death.
With my poor little freezing Ancistrus though, I wasn’t sure which of the two evils would be worse. I felt pretty sure that leaving him in the cold water would result in his death... I think that the temperature had a paralyzing effect on him, causing him to stop moving his gill plates but also slowing his whole system down and reducing his need for oxygen. Since cold water holds much more oxygen than warm water, I think this helped keep him alive while he was unable to move fresh water over his gills or come to the surface of the water for air.
I had to make a decision about what to do to try and save him. He had only been in the icy water for about 10 minutes, would it be better to move him slowly into warmer waters, using the acclimation method of gradually mixing new water in with the old? or would it be better just to dump him into warmer, healthier water? This is a dilemma I’ve always wondered about... exactly how long does it take for a fish to adjust to a new environment?
He had already had a nasty shock once (the cold water), and I wondered if the equally rapid change back to water resembling what he was used to 10 minutes ago, would do more harm (through yet again failing to acclimate), or more good (because the exposure to the poor conditions was for such a short period of time, that he had not fully adjusted to it yet).
I made the decision to get him into warmer water as soon as possible. I found an unused tank and dropped him into it. He stopped moving and lay on his side. I wasn’t sure if this new water I was putting him into was even close to what he had been in prior to the shocking cold and chlorinated water, but it was worth a try.
To my surprise, the next day he was swimming around as though nothing had happened. He recovered from his ordeal without even coming down with an outbreak of ich. Sometimes it really amazes me just how tough these little guys can be.