No, not a good idea. It can kill the fish. There's really no need anyway. The fish and plants have a symbiotic relationship. It's a delicate balance. The plants supply the fish with oxygen and food. The fish supply the plants with fertilizer (when they poop & pee) and carbon dioxide.

Beg to differ. Our local pond dealer uses John Innes no 1 for his pond plants. I was sceptical but it appears to work OK, so I'd have thought that a compost apparently formulated specially for ponds wouldn't be any more damaging than that. Don't put it loose in the bottom though, just in the baskets.

Agree with Stera. only in aquatic baskets not in pond itself.

Stera - we are both essentially saying the same thing - not in the pond. My point was not to let the NPK leach into the pond water. The fish produce plenty of it and too much is toxic.

Will anyway Bathgate - aquatic baskets are slatted to let the water into them.

aquatic compost formula is low in nutrients and quite gritty to add 'weight' to the slatted baskets. John innes number 1 is also low on nutrients so some plants are sold in this.

I don't use any compost in an established pond but just plant into gravel and with large plants like lilies I tie them in to the basket using nylon fishing line, then back fill with gravel.

As said, natural wastes from fish will provide enough nutrients. though if you have many fish or very expensive ones [koi for example] check the ammonia and nitrate levels regularly. [I did a blog on my pond disaster called something like what a July and then an update. ]

If you do use aquatic compost a layer of gravel on the top helps prevent the fish disturbing the soil and clouding the water.

thanks for the info. my fish knocked over one of my large baskets and most of it leaked in the pond. I wasn't sure if i should leave it or not. How would i get it out? i've read there are these 'hoover filter' things that suck the dirt out, filters it but then sprays the clean water out. Thanks for the help guys

I don't have a pond, but I have indoor aquariums. As regular maintenance, you should have a vacuum device or siphon. Just the one basket isn't a big deal.

I did have one of these pond 'hoovers' and it was a waste of money. so places hire them out but and it is a big but you do not know how sterile it is. has it been used in a pond with infection? 2 of our local fish ponds have been infected with some virulent disease, probably brought in on undipped landing nets. so again I'd be wary. One basket of compost isn't going to do any damage in the long term.

trying to scoop it out will just circulate it even more . in time some plants will root into it.

We don't have any fish in our pond Paul - the heron sees to that! I don't like nets so we do without.
Re the spilt compost, as time goes on rotted weed etc will gradually turn into a sort of compost anyway. Natural ponds all have muddy bottoms.

Stera, by definition a FISH POND has FISH. That's what the question concerns and what I assume.

Oh dear, put my foot in it again....

why have you put your foot in it stera, one of the fish ponds near us is devoid of fish. it has been wiped out by disease. still a fish pond though. they were a traditional design in monasteries from the 9th century onwards. not sure when they will restock this one.

The application of aquatic compost is quite a different story if you don't have to worry about poisoning the fish. Two different scenarios. That's why I said "not a good idea" if you have fish swimming in the same pond.

No probs Seaburn, just wanted to avoid a long discussion...

We use aquatic compost in our pond, and have about fifty goldfish. They breed every year and grow at a tremendous rate of knots, so it doesn't seem that the compost is affecting them.

Im not trying to win an argument. Im just throwing out a word of caution about adding chemicals to your fish pond with live fish. You can add whatever you like, but you can't take it out once you do. An overdose will be a painful and costly mistake. You should at least check the Ph level of the water which fluctuates regularly especially if your pond is catching rain water too. Ive read mixed reports.