15% water change every week from now on should be fine.
Oh, and don't worry, just do your weekly water changes, and if your fish are hardy enough, they will be fine.
I have found that all of this is nowhere near as exact a science as everyone on this forum makes out, all this nitrates ammonia stuff, yeah, if you have really bad levels some fish may die, but really, for these fish to have survived millions of years of evolution, they must be doing something right when it comes to survival, and as long as you don't have any large amounts of toxic stuff in the water they will be fine (by the way, soap will kill your fish, never wash anything in your aquarium with soap).
I also recommend getting:
2 of these for algae cleaning:
<a href="http/en.wikipedia.org/wiki/Otocinclus" target="_blank">http/en.wikipedia.org/wiki/Otocinclus</a>
DO NOT GET THIS:
<a href="http/en.wikipedia.org/wiki/Chinese_algae_eater" target="_blank">http/en.wikipedia.org/wiki/Chinese_algae_eater</a>
<a href="http/www.aquariumlife.net/profile-images/algae-eater.jpg" target="_blank">http/www.aquariumlife.net/profile-images/algae-eater.jpg</a>
And some bottom feeders, maybe a small loach, I suggest Kuhli's:
<a href="http/en.wikipedia.org/wiki/Kuhli_loach" target="_blank">http/en.wikipedia.org/wiki/Kuhli_loach</a>
Or Corydoras of any sort you see in a fish shop.
Sorry, but this is amonst the worst advise I've seen on this forum to date.
I must agree with Peter here. That's pretty bad advice.
Matty, don't clean anything for now. The most important thing in a fish tank is the filter, and it doesn't just filter out dirt as you may think. Actually it's main function is to house 2 bacteria colonies which are vital to your fish's survival.
Ammonia is present in any tank where there is fish as it is produced by fish doing the toilet and they also excrete it from their gills through respiration. Ammonia is lethal to fish even in very small quantities. The first bacteria colony convert lethal ammonia into nitrite.
Nitrite is also lethal to fish, even in very small quantities. The second bacteria colony convert lethal nitrite into relatively harmless nitrate.
Nitrate can be harmful to fish in large concentartions, so it is removed from the tank on a regular basis.
You can see why the filter bacteria are so important, however they don't come ready to use with your filter. You need to culture them.
At the moment, your fish will be producing ammonia and there is no filter bacteria to convert it into harmless nitrate, so it is building up in your tank. This will quickly poison your fish and is commonly called 'New Tank Syndrome'. The bacteria will start to colonise the filter just by ammonia being present in the tank, but this generally takes a few weeks, and your fish are at risk in this preliminary period.
You can read more about New Tank Syndrome in the link called 'Cycling with Fish' in my signature below. In short however, follow OldMan47's advice of daily water changes. I would recommend that 50% is a good amount. Don't be fooled into thinking that changing too much water is bad for the fish. This is a common misconception amongst new fishkeepers and is totally incorrect. At this critical stage in the process, water changes are essential if your fish are to survive. Just make sure to match the temperature of the new water to that in the tank, and make sure the repacement water is properly treated with a dechlorinator, and you could change 100% if necessary.
Please also read the other link in my signature, 'Fishless Cycling'. Fishless cycling is another way of colonising the filter with the essential bacteria, but as the name suggests it is done without the presence of fish. This is considered much more humane as even with regular water changes, a fish-in cycle can damage the long-term health of fish. If it is at all possible to re-home your fish whilst you carry out a fishless cycle, please consider doing so for your fish's sake.
Otherwise, water change, water change, water change.
Either way, a test kit is invaluable at this critical time, and if you can stretch to buying one, it would help immensely, not only with keeping your fish alive, but also with your understanding of what is going on in your tank and it's effect on the fish.
It is important at this stage that you don't add any more fish to the tank as this would make the situation worse.
Hope this helps you.
BTT