and am I ok stripping it back comeplety and starting it again?
This depends on the condition of the pond and whether or not you have any fish. If you start over, you'll loose beneficial bacteria, but it may be worth it if the muck is deep enough. If there is a gravel bottom, consider taking the gravel out, as the biological load of the debris it traps far outweighs the surface area it provides for nitrifying bacteria.
If you have both fish and sludge, either take the fish out or clear only a small section of sludge each day. The reason for this is that the sludge will release poisonous gases when disturbed, and too much at once will kill the fish.
when you say "transferring the media from the indoor tank" do you mean the gravel at the bottom?
No. I was thinking of bioballs, potscrubbers, matala, feather rock, lava, etc. There are a few types of DIY filter that would allow you to include aquarium gravel, but I would never throw it in the bottom of the pond. The problem with gravel in a pond is that it traps too much debris. And because you can't use a vacuum in a gravel pond, it's very difficult to clean. Even with pipes to draw water through the gravel, it's a bad idea. Don't do it.
What you could do, though, is put your gravel in a filter bag and stick it in the filter or perhaps under the waterfall until your new media is colonized.
avons82 wrote: Hi! From advice I got on here I'm transferring my large indoor goldfish into an outdoor pond.
Do I need to treat the water as I would an indoor tank, ie chlorine balance etc.
Its just a 175gal pond for 3 fish. Do I need a filter?
Yes. One rule of thumb for goldfish ponds is 30-50 gallons per adult fish. Though you're slightly above this minimum, you still need a pump and filter.
Does the water need to sit in the pond a certain time before I can introduce the fish?
Ideally, you'd let the pond get through the nitrogen cycle with bottled ammonia and/or rotting fish food before introducing the fish. However, if you're going to transfer the filter media from their tank along with the fish, you could consider the pond more or less cycled.
And can anyone give me any advice on maintaining the pond? Water changes etc?
Do not add gravel, the effect of the muck it will trap will dwarf any biological filtration the gravel provides.
Remove debris from your pond and filter regularly.
Instead of guessing about when to change water, get a test kit. The liquid tests are much more reliable than the strips.
Marginal plants (the ones that stick up out of the water) have the advantage of not causing pH swings at night.
Much of what you've learned from keeping fish indoors applies to ponds, but there are some differences. More sunlight means algae can be much more difficult to control. Your filter will have to cope not only with the load of the fish, but also with debris from trees and other plants. At times, there will be enough pollen to noticeably effect water quality. In the summer, heat may be a problem. Be sure you have enough aeration to keep the oxygen levels up. Herons are much better at fishing than any domestic cat could hope to be. Your fish will share their pond with wildlife. Some will be good to eat. Others, for instance, frogs, may compete for the attention of the fishkeeper.
The usual rule of thumb for goldfish is 30-50 gallons per adult goldfish. The requirements for a fish go up roughly with the square of length, hence four 5-6" fish roughly equal one full-grown fish, but of course they'll keep growing. I think you're likely to start having problems as your fish grow. And if they continue to reproduce successfully, you're looking at a Malthusian crash.
Besides finding a new home for some of your fish and/or building a bigger pond, you might want to think about adding a predator to eat the eggs and fry. Here in the US, ponders often use sunfish for this purpose, being careful to have only one fish, fish of all one sex, or less fertile hybrids, lest the sunfish themselves overpopulate. I wouldn't recommend these fish outside of their native range, but I'm sure you have something over there that could do the job.
Bloodworms are often said to be a good sign because many of the water conditions that are bad for fish will kill midge larvae. I'm not sure if that's true, but at the very least, you've got free fish food.
Yes, the nitrate cycle is the same in a pond as in an aquarium. And just like a tank filter, you can cycle your pond filter with live fish, fish food, bottled ammonia (without additives), or some combination of those options.
Bazzer wrote: I would definitley agree about the test strips, as usefull as a choclate teaspoon.
But not as tasty.
Is there a date on that pack of strips? My guess is they've been sitting around too long. Not that I recommend you go out and buy a new batch. The only thing they're good for is to make frequent, but not very accurate, measurements. But if you're concerned enough about something to check it often, a test that might be sortof accurate now then isn't going to cut it.
I'm sorry to hear that your comet didn't pull through. I suspect that there wasn't anything you could have done, but of course you had to try. If you really want to know what happened, a necropsy by a qualified vet (or even an interested amateur) might be useful. But considering that all your other fish are healthy, I don't think it's really necessary.