does anyone here have koi's in there aquarium? i purchase 2 small koi's from a LFS and they are in my 55gal tank. now i dont know if they should be in a pond or aquarium. right now everytime i pass by my tank, they are constantly flashing. they eat a lot and nitrates shoot up to 40ppm each week, therefore making me change the water weekly. i had two large ryukins in the tank with them and every time the koi's flash, they frighten my ryukins. i eventually pulled the ryukins out and placed them in my backup 20gal tank.
so i'm just curious, how many people here have koi's in there tank?

Koi really belong in a pond. They need around 300 gallons to be happy. A 55 gallong tank might be okay while they're small but once they get over 5 inched you need to find them something a lot bigger to live in. The flashing sounds like paracites though

Did you quarrantine them before you added them? PArasites could very well be the culprits,but poor water quality can also do that,along with big water changes at times.Have they flashed since you've gotten them,or just during the time when the Nitrates start climbing,and the water needs changing?
Can you take a peek at their gills?Are they red.meaty,or pale pink,tattered looking?

First Koi don't belong in a tank. The only reason that they should be placed in one is in order to QT them before they would go to the pond. Koi should have 250 gallons per fish.

Second koi really don't like being in an Aquarium. They hate being watched from the side. The best thing to do to keep them from getting excited everytime you walk by the tank is put something around the tank so they cannot see you. That will calm them down.

I kept two koi in a fish tank over last winter only because when they got here they needed to be put in QT and by the time QT time was up it was too cold to put them out in the pond.

Scott

my koi's defintely dont have parasites, cuz i'm running a UVS 24-7, and you're right. koi's dont belong in a tank. i need to find someone who has a pond to take them. thanks for everyones help.

Deffinetly Don't? Fondoo, I'm going to disagree on that.. Why? Not all parasites can be seen with the naked eye! It takes a slime scrape and microscope to honestly say they don't have parasites and even then you can miss them. A UV light is not going to do much for what is attached to a fish either! And to the best of my knowledge, doesn't knock out the bugs anyway. While we think of ich being those white salt/sugar looking spots all over a fish, even those sometimes don't show up with out doing a "scrape and scope", especially with Koi, Ich can't alway's be seen. The rule of thumb is to do a scrape and scope 3x3, 3 fish, 3 places, 3 times.

Flashing & excess scratching can be a sign of parasites, or it can also be the ph/gh/kh irritating them.

And no, Koi don't belong in AQ's, by the time they are 2 years old, they should be around 12" plus, give or take. They average around 32-36 and as high as 56". Keeping them in a AQ only stunts most of them for growth, but there's alway's the odd one out that keeps growing and growing.

I bought 2 of the best looking butterfly koi that I've ever seen. I have them in a 29 gallon tank.