New koi's in my pond?

Question

I have 5 big Koi's in my pond which I have had for many years, and recently bought 6 new koi's to add to the pond. Am I suppose to seperate them first before I put them in with my old ones? Because it seems each time I add a new fish to the pond a few of my fishes would die. How can I avoid this problem? Are you not supposed to add new koi's in the pond straight after buying? Help needed please!

and now one of my old fishes keeps laying on its side :S

Answer 1

Yes, you need to hold the new fish separate from the pond for at least 2 weeks to be sure that they carry no diseases that could infect your pond. Each time you add fish it will cause an ammonia spike in the pond which is the most likely cause of the deaths each time you add fish. This can best be avoided by only adding 1 new fish each 2-3 weeks.

MM

Answer 2

It would be a good idea to quarentine the new fish to observe for any diseases that can be passed on to your new fish for a couple weeks. Depending on the size of your fish, you might use a large tank (a 30 gallon tank will cost you about $100 and can hold three medium koi) that has already been cycled and ideally has water from the pond they'll be living in.

The first rule to adding fish is float thier bag on the surface of the water to stabilize the temperature of the water in the bag to the water of their new home - either the quarrentine tank or the main pond - a sudden change in temperature can shock and kill a fish. The second is to add water from the pond (or quarentine pond) into the container that you brought them home in. Do it slowly, and wait between additions. When bringing fish home, I generally add in a quarter cup of tank orpond water per inch of fish and wait 15 minutes before adding more. Remove any spilling water from the container and add more water for an hour - about 4 times. Don't add water from the store to your pond, as it can contain diseases. Net the fish and add it to your pond that way.

As to the rest of the problem - if you observe all fish on the surface of the water gasping for air, then it is a problem with oxygen. You can buy powerheads from your local petstore and plug them in. A lot of models are fully submersible, and all you need to protect is the plug. A few of these will add water movement and oxygen to the pond.

If all the fish are lethargic, their gills and side tarnish or turn red, a spike in ammonia is probably to blame. Too many fish too soon will cause a large spike in ammonia and acn kill some fish, especially those stressed from being transported.

Since the deaths seem to occur when you add fish, I'm leaning towards the ammonia problem. This can be remedied by adding fish slowly, testing water with a test kit and doing partial water changes when ammonia reaches unsafe levels.

As for your fish floating on it's side, it it's not dead, it's suffering from ammonia poisoning. Changing 30% of your pond water isn't exactly a feasible feat like in a smaller fish tank, but you can set up a tank (or even a clean 10 gallon storage bin that has never had chemicals in it, depending on the size of the fish) filled with 2/3's pond water and 1/3 dechlorinated, conditioned water to put the fish that seems to be in distress in. It should recover within a few days and be good as new! As for your new fish, I'm afraid you might lose some if you don't happen to have the room handy for them outside of the pond, which not many people do. Hopefully they all will survive.

The good news is your biological filter will catch up soon and you can add the fish back into your pond.

Answer 3

I think seperating them in a smaller pond for 2 weeks would keep your healthy kois ok.

Answer 4

it's possible there isn't enough oxygen in the water,it depends on how big your pond is! did you leave them in a bag with the water so they can acclimatise to their new home?if not this can kill them,hope this helps,good luck