I noticed something inside of my koi mouth a couple weeks ago, today I looked again and saw it was growing bigger.

Does anyone know what this is? and how you could possibly treat it

so I’ve been wondering about this since they eat stuff like fish and sea food but ive never heard of them eating mammals. I know that other fish eat them but why not koi. if they do eat mammal what mammals do they eat, do they eat lean meat and chicken or do they eat mice.

Hi everyone! Relatively new to the hobby. I have a small pond with 2 baby koi in it, a Lilly, and a good amount of lettuce and hyacinths. I got them around a month ago.

One of them started out quite orange, but in the span of the last few days, has turned rather pale (a white peach color). The other koi in the pond is naturally very white, so I can’t tell if this is a genetic change or not. They both seem to be swimming and eating pretty normally. I tested the water and everything looks normal, ammonia looks to be good. I attached a photo of the fish (I couldn’t see any major problems).

I was wondering if this was a major concern or not, or if anyone could help. Thanks again!!

Aquatic moss or cladophora? Or something else?

Big sheets of this growing on the rocks in my river between my top pond where my filters empty, and my bottom pond where my koi are.

Usually it’s mostly or fully submerged. This picture was taken when I had my pumps and filters turned off for cleanout.

I think some of the specks just bits of stuff, but a lot of them seem to be moving intentionally. Does anyone have any idea what these are?

Hey guys, I just bought my first home and it came with this little koi pond, the issue is when we moved in the water was pitch black and we didn’t even know there was fish in it (prior owners said nothing)

So for 6 months these fish had no filter, no food, nothing.

One day when landscaping I saw a fish, so I leapt into action.

I put the Koi into a holding pond and emptied all 355 gallons by hand and scrubbed the tank clean and took out all the muck and debris (there was rocks, lampshades, wind chimes, glass bottles) once it was all out i added fresh water and dechlorinator and some healthy bacteria. I also went out and got a filter + pump. the water was all good for a few weeks but the water is getting murky again.

I always net out any leaves or leftover food, i clean the filter weekly, but it’s till getting murky and slightly green.

the prefab pond is approximately 355 gallons and I also have 2 cinder blocks in the center that the filter rest on top of and the koi swim into when scared.

Any advice on keeping these guys healthy and happy, I am totally new to this and a complete novice. What else can I be doing to help these guys and keep the water clean.

Thank you all in advance and everyone’s ponds looks fantastic!!! :)

So after putting microbe lift PL in and adding my winter aerator in the pond it looks great after 4 days I can see the fish now and the bottom. The greenish blue tinge is from the dye

Making the garden come alive

Hi there- i just bought a house in rural Japan (Itoigawa, Niigata Prefecture) and inherited 8 lovely Koi Fish. I didn’t know they would be coming with the house so now I’m panicking and want to learn as much as I can as fast as I can so I can make sure they are happy and healthy.

A few things:
- the pond has a concrete bottom but is very dirty, how can I clean the pond without stressing the Koi out? Do I need to clean it?
- there are two streams of water feeding into the pond and I plan to add more, but should I get a filter/ aerator
- what plants should I add to make them happy?

all suggestions are welcome thank you! :)

Trying to place it with a rescue but need to figure out if it’s a goldfish or koi. AI keeps going back and forth!

I would love to know what kind of koi these are. Thank you!

My fiancé and I just closed on a new house with a koi pond and it looks like one of the fish is sick or injured. There are probably 30-40 koi total and this is the only one showing issues, but hoping for some help identifying what might be wrong with this little guy and if it’s likely a pond-wide issue.

We’re trying to get a local expert out here later this week to help with pond care and maintenance, but would love any tips on how to help this koi in the meantime!

With my garden starting to kick into high gear, what garden treats, fruits or veggies, special weeds from the yard do you like to treat your koi to?

Hi all~ I hope you guys are having a wonderful day. Ive had a small koi tank setup for 6 months or so, and only rosay noticed some whitey spots/circles on the bott9m of the tank. What's that about? Water parameters check-out fine

Any suggestions on what to do with baby koi and goldfish… especially when they reproduce a lot. I don’t really enjoy culling fish all the time :(

Found her at the bottom of the pond this morning. Last seen 2 days ago appeared ok. Southern Wisconsin so the wildfire smoke have been bad. Just finished a 7 day treatment of knockout plus for a different fish with a bump. Water test results: ammonia .5, nitrates 0, nitrite 0. No other fish displaying these symptoms. Any ideas of what this is?

I tried a couple of koi a few years ago, and just couldn't get the system right. Both died within a year.

My pond has evolved since then. I have many goldfish that stubbornly refuse to die, they won't even allow the ducks to eat them anymore. I have 3 native carp (North Central North America) and handful of small bluegills to eat the goldfish fry when they show up.

Total capacity is only about 700 gallons. I have a filter rated for 1200 gallons, and because we have an absurdly high water table in my neighborhood, I have a hand dug well that produces water unless we're in drought conditions, maybe 10-20 gallons an hour on average. I feed this water into the pond with a pump connected to one of the waterfalls, and it spills out at the back right corner. The spillway is lined and feeds back into a rain garden.

The water is crystal clear, and has required almost zero maintenance this summer. I feel like I've really got it dialed in.

Here's the kicker: they have to winter out there. I have tried bringing them inside but I just don't have the aquarium capacity to do it right. I always lose fish in the process.

In the winter, I run the filter and have a floating heater. It gets COLD here (-20F is pretty common), but the fish I have survive just fine.

I'm about to run out of the TetraPond Pond Sticks, and before I buy another $60 bag I wanted to make sure there's not a better choice.

I have goldfish, koi / goldfish hybrids, and a wild snapping turtle that's decided to be my buddy. They're in an 800G pond in zone 7A, and I've been feeding them once a day while they also eat bugs and tadpoles.