Why have most things died in my pond?

[Kreacha]

On returning from a five day holiday recently, all of my pondsnails (about 30) (they have come out of their shells and some of their bodies have swollen bubble-like protrusions), and several waterboatmen were found dead in my pond. I also had two frogs and they had disappeared too. The pond had turned quite slimy and green.

The pond was put in this time last year and I haven't had any problems with it. The pond is about 4 foot long x 3 foot wide x 2 foot depth. It has oxygenating plants in it but it doesn't have any running water going to it and it doesn't have any fish in it. It is situated where it gets the sun most of the day on half of it and the other half is shaded. I thought the pond would be able to look after itself but is it because there is no water flow to it that everything is dying? (although it has been there for a year and this is the first time this has happened). The only other thing I can think of is that there is trailing lobelia hanging over the side, would this maybe poison the water? Anybody have any thoughts? Thanks.

[Kayleigh]

Sounds like pollution no running water is not a problem my pond is 4 years old its doing fine.
Have you or did you have a water lily it sounds like something has died and turned the water bad can you remove all the water rinse every plant and refill with clean water..
If you can add some yellow flag iris they filter the water naturally but keep them in a container as they tend to take over otherwise.
But it needs to be drained asap.

[Littlesparrow]

In hot weather pond critters can suffer from a lack of oxygen, some pond plants will help by adding oxygen and providing shade. I have a smallish pond and have also followed the advise of another member and the over flow from my water butt now goes into my pond so that after heavy rain the water has the chance to be renewed .

[nightshade]

Could it be chemical run off from a neighbours garden or adjacent land, the sudden greening could indicate a fertiliser contamination

[Kreacha]

Originally Posted by nightshade

Could it be chemical run off from a neighbours garden or adjacent land, the sudden greening could indicate a fertiliser contamination

Hi Nightshade, we are the first house on the corner of a cul-de-sac and where the pond is, it hasn't got a neighbour, good theory though, thanks.

[Kreacha]

Originally Posted by Littlesparrow

In hot weather pond critters can suffer from a lack of oxygen, some pond plants will help by adding oxygen and providing shade. I have a smallish pond and have also followed the advise of another member and the over flow from my water butt now goes into my pond so that after heavy rain the water has the chance to be renewed .

Thanks LS, pond does have a variety of oxygenators though and half of pond is shaded if critters want to get out of sun, I'm wondering if what Kayleigh has said is the cause (something has died and made the water go bad, dunno what though ).

[Kayleigh]

Originally Posted by Kreacha

Thanks LS, pond does have a variety of oxygenators though and half of pond is shaded if critters want to get out of sun, I'm wondering if what Kayleigh has said is the cause (something has died and made the water go bad, dunno what though ).

Plants can do this as well as frogs ect they would put extra nutrients into the water and cause it go green..
If there is a black oily scum on the top with a rancid smell then empty it.
otherwise half empty and refill with fresh water..

[Kreacha]

Originally Posted by Kayleigh

Plants can do this as well as frogs ect they would put extra nutrients into the water and cause it go green..
If there is a black oily scum on the top with a rancid smell then empty it.
otherwise half empty and refill with fresh water..

Actually now you mention it, there is an oily residue on the surface, I thought this may have been off the sparrows that have been bathing in there recently though. I'm wondering if it is the overhanging lobelia's flowers that have rotted and ate by the snails who then pooped them out, polluting the water .

[tom00_uk]

have you recently added new plants?

[posie]

Lobelia is very toxic..deadly poison...has been used to murder people by poisoning...Get rid of the lobelia, and do as Kayleigh says change all your water and remove any lobelia in the pond, even if it's rotted..

Posie..