Scales missing on Koi

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dmk

AC Members
Apr 28, 2007
61
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6
Western NC
I just noticed my new Koi has an injury on either side, low, right between the 1st and second set of fins. He's very light colored there, so I could have missed it when I got him (I've only had him for three days).

I tested the water with a good test kit and everything is good. The fish don't seem to be fighting at all (he shares the tank with three Goldfish). He seems very energetic, swims and eats normally. There doesn't appear to be any damage to his fins and he has no parasites or fungus that I can see. I don't see anything sharp in the tank that could have hurt him.

Any ideas?
 

wataugachicken

The Dancing Banana
Jul 14, 2005
5,451
1
0
Charlotte, NC
do you have a heater on the tank? could be be swimming too quickly and scraping himself on filter intakes?

on a side note, what size tank do you have, and what do you plan to do with the koi as it gets bigger?
 

Flaringshutter

Befriend a feeder!
Oct 17, 2006
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Southern California
Koi and goldfish are apt to lose a scale or two quite often. It's a normal thing, especially for male koi and goldfish. They grow back, it's not anything to be too concerned about it. If the area is red or inflamed, then you definitely have an issue and the fish should be medicated. Keep an eye on him. I think you'll find everything will turn out okay.
 

dmk

AC Members
Apr 28, 2007
61
0
6
Western NC
Thanks for the replies. That makes me feel a little better. He is an aggressive swimmer, always swimming back and forth across the tank, swimming in the air curtains or doing the treadmill thing on the water jet from the filter. I suppose he could have scraped himself on the filter outlet or maybe on a rock, but none of them appear sharp.

No heater. If anything I'm having trouble keeping the tank cool. Water's been about 70 and it's 74 today. I installed my A/C this evening so I'll have to start keeping the room cooler. May start using cooler water changes.

55gal tank. He's only 3" or so right now, just a baby. As soon as he grows to about 6" or so, he's going in a big outdoor Goldfish pond. He may go sooner if he keeps hurting himself.
 
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Flaringshutter

Befriend a feeder!
Oct 17, 2006
1,870
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Southern California
you know, koi and goldfish are actually temperate fish, not true coldwater fish. they can survive in a huge range of temperatures, everything from frozen-over ponds to low 90s. however, they do best from about 65-85. they're most susceptible to disease from 65-73, though, so I keep mine in the high 70s, usually about 78.
There's a big debate in the goldfish community about the best temperature for goldfish, but I would say that they might best be described as "cool tropical" fish. It does increase their metabolism and therefore waste production, so frequent water changes and good filtration are a must, but I would argue that they shouldn't really be kept at such cold temps as the 60s.
I think your tank will be fine at the temps you have. Just my .02. Something to think about. :)
 

dmk

AC Members
Apr 28, 2007
61
0
6
Western NC
however, they do best from about 65-85. they're most susceptible to disease from 65-73, though, so I keep mine in the high 70s, usually about 78.
That's interesting. I was thinking they preferred cooler water. Here I was worried that high 70's was too warm for them. The more I read about Goldfish, the more I realize everything I thought I knew, was wrong.
 
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