I think our pond (I reckon 2-3m2 in surface area) may be a bit overgrown. It’s home to a dozen or more goldfish.
My questions are
Thanks as always for any advice.
Sorry to be flippant, but if you can’t swim in it, it’s overgrown. 
I’m sure someone more helpful will be along very soon, says he having just come back down thoroughly refreshed after my 32 metres. 
I’m afraid that I can’t help with horticultural advice, but when you uproot plants from the pond, leave them on the margins for 24 hours at least. This gives any wildlife who have made the plants their home a chance to scope out another nearby property!
(Apologies if you are already aware of this…)
It is a bit crowded so you could probably pull a few plants out. Leave the water lillies - they provide shade and protection for your fish. Dont know if you’ve got any oxygenating plants but the ecosystem can’t be too bad as the fish are still alive.
I’m thinking about what to do with my pond - the oxygenators are taking over
Edit: and what @_Brian said
Thanks all.
We inherited the pond when we bought the house. I don’t know what the plants are, apart from the lilies.
I don’t want to fiddle with it but the amount of vegetation has definitely increased.
Are lilies oxygenators?
Yes, water lillies do oxygenate, but there are better plants (generally with a lot more smaller leaves - increased surface area).
We are about to do the same but much larger. Being complete pond novices all replies will be filed in the appropriate brain department.
There’s a lot of solar powered pumps/fountains on places like amazon.fr that are very cheap (chinese obviously🙄), and help with water circulation and oxygenating.
And what @_Brian said too….
What sort of pond is it? And size? A natural thing or created lined pool? With a natural source or rain and the water table?
We intervene as little as possible, as the fish will nibble to keep plants in balance. But I think yours does need a human hand!
We just had our (artificial) pond re-lined - the old liner was 20+ years and cracked and leaky like me) - also quite chocka with various plants.
The Pond Bloke chopped the big lily plant down to a more appropriate size and got rid of most of the pondweed - but said we should leave some to provide oxygen, which we did.
He scooped out the goldfish and put them in a tank temporarily - they seem very happy with the wide open spaces they have now (there is still enough veg for them to hide under).
My mother of course was straight online ordering new pond plants. 
At some point I will probably put a solar powered pumpy thing in - the old one gave up some years ago.
So I think some thinning out of your pondery won’t do any harm.
I’d focus on reducing the reeds. The pond can support a lot of plant life - the reeds however tend to be “bullies” once they get going and can take over. Don’t remove them all - but thin them back especially in the centre of the pond and around other prettier plants
You can be fairly ruthless reducing pond plants. Leave the water lilies, the big leaves shade the surface and provide hiding spaces for the goldfish. Other plants, take out, hack about 1/3 off to put back into the pond. Leave the other 2/3rds for 24hrs near the pond to give creepy crawlies a chance to get back in…
Then compost.
I had to do this about every 3 years to my ornamental London pond or there was no water to be seen.
This is most important, I never dredge the bottom these days because there is so much life in creation down there, but I do remove leaves and small branches from the surface from time to time and I empty the net onto a sloping part of pondliner and then riddle about to make sure the whole population gets out to sliver down the slope back into the water. Some are not that bright and head uphill instead so have to be helped with encouragement to turn around.
Yes, my Amazon aerator, powered by a small solar panel has been going 365 days a year for 2 years now and pond now completely slime free.
That would have been my suggestion too. We don’t have reeds (yet), but we do have flag iris, and it has literally taken over nearly half the pond, so it will be up for a drastic thinning in the autumn.
This is a job for spring in march or April, l would leave it alone until next year. I have a tiny pond about 1m2 with a lilly in the middle in a pot, marginals planted around the edges and submerged pondweed for oxygenation which reminds me of the village green pond in my childhood.
In spring you can be ruthless because pond plants grow vigorously
