I have a backyard koi/goldfish pond. I live in a cold weather region and my pond freezes solid in the winter. So, I annually move the fish to a 100 gallon tank in my garage from November to April. The winter tank has a filter and two air pumps.

Six out of 19 fish have died in the past month. Before this, it had been a few years since a fish died.

Initially it was a few of the smaller fish dying (10-12 inch), but now a couple of my largest koi (20ish inch) seem to be unhealthy and dying also.

I tested my water quality a week ago, and the nitrate and nitrites were high. I replaced 10% of the water and thought I was in the clear, but now it appears more fish are in the verge of death.

Any feedback on how I can remedy help my fish? Thanks Reddit.

Does any koi expert know what this is? Their skin is like deteriorating by their mouths and there’s red all across the body. The fins are deteriorating as well. My pond guy said Melafix but I’ve tried many times and it hasn’t worked.

Got this beautiful little one from PetSmart the other night, was the smallest and most colorful in “assorted koi” category, in between the regular goldfish and larger butterflies. Can anyone identify and how young? She’s lively and active, adjusting well and responding to me so far.

My mother wanted to get rid of mosquito larva in the water feature she has outside of her home office. She bought 4 tiny koi and just dumped them in there.

They have barely any space in there. It's about the same size and depth if you laid a desktop pc on it's side.

The woman at the petstore who sold them to her clearly didn't explain how much space they need. It all feels so cruel and it's been upsetting me a lot.
My mother said she'd MAYBE by a tank for them in october of next year.

Can someone help me explain to her why she should just return them. I'm struggling to sleep at night.

I am looking to build a 5000 gallon raised pond which will be concrete foundation on 3 sides and a large pane of glass on the last side (3’ x 10’ hopefully). Can anyone tell me what type of glass i should be looking at and how thick should it be? Thank you!

12000 Litre pond, 4 x 3 x 1, currenty have 8 fish at size 20-30. I am going to add 2 more fish next january size around 50+ just comeout of azukari. I live in tropical country so no winter here, only rain.

My filtration is, I would say premium, the SSA of the filtration system is 3x required of that size. In addition i have bakki shower full with its media. And the pump turn around is at 2-3x per hour.

My aeration is at 1500 liter per hour connected to a dryden aqua.

Last time I tried adding fish, in august, half of my koi died (i had 20, added 2, died 14). Tho admittedly, at that time my filtration is not as good as right now and aerator was non existent.

Any tips on adding new koi?