skip to main content

Ponds & Aquatic Plants

fish deaths

16 years ago

I live in Dublin Ireland where the winters are quite mild, rarely going below zero Centrigrade(32farenheit). I have an external pond less than 3000litres capacity . A shelf on three side about 300mm deep with the centre about 1metre . A few years ago it contained 225 goldfish and 1 large koi .I got rid of about 125 fish - too expensive to keep , also Mr Heron helped . I had about 100 till 14 days ago . They started dying so now I have about 5 left including the koi.I brought a few dead ones to the vet. Some ,not all had a sheen of white around them . She performed an autopsy(!) on one . Could not discover anything unusual . Gills were OK . The white sheen she said was a secondary infection . It could have been because of overcrowding . The fact that 225 had lived happily a few years ago was because of the fact that the winters were a small bit colder and that the winters could have killed the bacteria . This winter has been quite warm in comparison. She told me to change the water , but keeping some and to put some salt in . Any ideas because I dont want this to happen again . By the way these 225 fish came from 5- yes 5 fish which I put in there about 10 years ago when I dug the pond . A lot of maintenance but well worth it. Thanks

Sort by:Oldest

Comments (3)

nancyd
16 years ago
What's the diameter of your pond - 15 feet or so? It seems that you had way too many fish that your pond could safely support. I think the deaths can be attributed to the overcrowding, not the weather. It was just a matter of time. A friend of mine is a biochemist and did an experiment with a fish tank ... he kept adding fish to see how many the tank could handle. Unfortunately he had no warning of anything dire until they all up and died one day. Nature took it upon herself to remedy the problem. Too many fish create too much waste which leads unhealthy water quality which leads to disease and ... dead and sick fish.

I copied this off a UK website (since you are more familiar with the metric system) as an estimate on how many fish a pond can safely handle. Hope it helps. Sorry you lost your fish.

HOW MANY FISH?

To assess how many fish your pond will support, estimate its surface area and allow 60sq cm of surface for every 1 cm of fish (equivalent to 24 sq. inches per inch of fish). Since fish grow and breed, it is best to start off with around one-third of the theoretical maximum number. For example, a 1.8 x 1.2m (6ft x 4ft) pond will, in theory, support 360cm (144ins) of fish, equivalent to 36 individuals averaging 10cm (4ins)long, but, in practice, you should have only about 12.

Golden Rule - Your pond needs to have part of the area at least 60cm deep for goldfish and 1.5m or more for Koi if they are to be left over winter safely in the pond.
garry_gardener
Original Author
16 years ago
Thanks very much for your advice . I've worked it out that really all I can have is about 70 goldfish - a lot different than 225! There are only two fish hanging on at the moment , and I would say that in the next day or two they will be gone. What I will do when they are all gone is clean the pond out and start again from scratch Thanks again .But I think I will leave that till later on in the Spring
Related Discussions
weather change fish death
Q
Comments (7)
Tina, you would have to treat the water for parasites. Melafix would not do that. You can purchase parasite treatments at a pond store or pet store. Follow the instruction to a "T" as it can be powerful stuff. Treatments usually are done over a few days with measured doses. Stay away from using straight Potassium Permanganate,should anyone suggest using it, unless you know exactly what your pond gallonage is and what you are actually dealing with. It is too easy to overdose with P.P. and end up killing everything in the pond. I dose my ponds, with a treatment, in the fall before closing them up, just as a prophylactic against parasites. "Horton"
...See More
Fish Death over Weekend ;-(
Q
Comments (11)
Well...to update: I have 2 sick ones still that I can see. The third sick one is missing. I think it must have died...and got eaten by a bird or turtle. I have not seen it since Sunday evening, after I dipped it in medicine. The other two are still acting very sickly...I do not think they will make it. The rest of my 12 fish are fine...hopefully it stays that way. I have done all I know how to do. coombs you are right....I have had ponds and aquariums for 7 years now...and it is one thing to lose a fish to a predator, or natural causes...but when you know you are directly responsible...it is heart wrenching. Part of me wants to put these two out of their misery, but I want to give them a fighting chance. I know they are just fish, but knowing that they are sick because of me is the worst feeling. When I first got into ponding, sad to say, I must have killed like 10 fish...same story with the aquarium. Then I did my research and learned my lessons. This is the first time this has happened to me in a while. It will be very hard for me to get new fish again in the future. I get nervous every time...because of stuff like this. Amanda
...See More
Chainsaw exhaust killed fish
Q
Comments (22)
Chicka, all the other goldfish are at least 3-4 yrs old (much larger) and they show no ill effects, thank God. Only problem with them was they would not come to the surface, probably instinct. I really thought I was going to have to get rid of my pond. It's not the greatest, but I do love sitting by it and watching all the wildlife and nature. Another thing I noticed was a snake skin, but garter snakes get in the pond every summer and have never left an oily film and they don't leave dying fish behind. I try not to get upset too much when the snakes eat some fish. They keep the number of new fry in check. I welcome all nature to my pond, except man made pollutants! ~~~~grrrrrrr~~~~ ;)
...See More
Fish Death
Q
Comments (4)
Horton, The co-worker didn't know if it was plugged into a GFCI receptacle. I talked to an electrician about this and his opinion was that if the light was just leaking (this is my word, not his - he probably used a more technical word) electricity, and had not shorted out, a GFCI might not have helped. That may be why the co-worker just got a shock and not killed from it. I don't know. I just know all those babies (now grown up) are dead. Yes, Helen, my co-worker was fortunate she wasn't injured. Anne
...See More
sleeplessinftwayne
16 years ago
Hey there, Garry. Just a thought, do you test the water for ammonia, nitrates, nitrites, etc? That could avoid problems expecially if there is overcrowding. Sandy

Related Stories

GARDENING AND LANDSCAPING How to Make a Pond

By Mitchell Parker

You can make an outdoor fish paradise of your own, for less than you might think. But you'll need this expert design wisdom

DECORATING GUIDES Designing Nemo: 30 Fish Tanks Make a Decorative Splash

By Mitchell Parker

Bring an otherworldly glow and a calming vibe to your home with the living art of an aquarium

PRODUCT PICKS Guest Picks: 20 Fantastic Bookends

By Morgan Spenla

Literature, comics, travel guides ... whatever provides your reading fix, you’ll find a bookend here to match

MODERN ARCHITECTURE Keep Your Big Windows — and Save Birds Too

Reduce bird strikes on windows with everything from architectural solutions to a new high-tech glass from Germany

FEATURES How Tupperware’s Inventor Left a Legacy That’s Anything but Airtight

By Mitchell Parker

Earl S. Tupper — and his trailblazing marketing guru, Brownie Wise — forever changed food storage. His story is stranger than fiction

MORE ROOMS Warm and Cozy Wildlife and Hunt-Themed Inspired Rooms

By Between Naps on the Porch

HOUSEPLANTS 8 Essentials for Healthy Indoor Plants

Houseplants add so much to our homes — and can thrive when grown in the right conditions. Keep these tips in mind

COASTAL STYLE Fishy Business: Tilt the Scales With Aquatic Decor

By Kerryn Ramsey

A marine element can add a splash of whimsy to your home

HOUZZ TOURS Houzz Tour: Country Cabin in Virginia

Simple family retreat is a comfortable place to take a break from modern life

LANDSCAPE DESIGN Koi Find Friendly Shores in Any Garden Style

By Marianne Lipanovich

A pond full of colorful koi can be a delightful addition to just about any landscape or garden

Sponsored

Dream Baths by Kitchen Kraft

12 Reviews

Your Custom Bath Designers & Remodelers in Columbus I 10X Best Houzz

More Discussions

Leak in my small inground prefab watergarden...?

1

pothos with yellow leaves

7

Stock tank cracked, New tank has brass drain

1

Growing impatiens in water

1