* Remove algae on surface of tank with an algae scraper before you siphon out water.

* As name suggests you need to remove 10 to 15% of water from your aquarium.

* There is no need to remove your fish to a separate container.

* As you remove water use siphon to remove messy deposits in gravel.

* In case you have an under gravel filter, then you would have to clean gravel during weekly water changes.

* Do not take out all ornaments and decorations and scrub them clean because you might destroy some of much-needed beneficial bacteria that act as natural biological filter.

* You can clean filters during weekly water change but do not change all cartridges, sponges, carbon packets, etc., as this might remove all good bacteria and harm your goldfish in long run.

* Also remember to rinse any new filter media in cool running water before introducing it to system.

* Once you have siphoned out 10-15% of water and most of dirt and alga, it’s time to replace amount of water you removed with fresh, dechlorinated tap water which has been left at room temperature over night, in container free of soap residue.

* Use a siphon to transfer fresh water into tank as this would be a gentle way to put water back in and it won’t disturb plants and gravel. You would also spill a lot less!

* Do make sure that fresh water is of somewhat same temperature as water in tank. You cannot just dunk in cold water because Goldfish are not tropical fish. Do remember to leave enough space between top of water and tank hood so that your goldfish get enough oxygen to breathe in.

What not to do:

* If you see that level in your aquarium has gone down, do not simply add water to make it level again. This is harmful, as you are not getting rid of impurities in water. You are just adding water without removing dirt and thus making water harder and more difficult for goldfish to live in. So don’t add water to top off tank, do a partial water change.

* Never add water directly from tap. Please keep a separate container only for aquarium use and leave water overnight so that harmful chemicals and chlorine evaporate.

* Please do not skip weekly water changes because if you do not partially change water, you are allowing build up of waste products like Nitrate that are not removed by filter, and contribute to growth of algae.

• Check out fins. Make sure that dorsal fin is straight and stands up. The backs of goldfish should be smooth, without unsightly bumps. Also check that all fins are healthy, even and are not rotted away or damaged. In all, a Goldfish should have a dorsal fin (unless it is a goldfish without a dorsal fin), pectoral fins that extend out on sides, two anal fins or one right in middle. Beware a goldfish with just one anal fin that’s placed kind of off to one side. It could mean that other anal fin is growing inwards and that could be fatal to goldfish.

• Inspect looks. Make sure that you give goldfish you are choosing a thorough look over. See that fish has a nice symmetrical shape and make sure they don’t have large heads compared to their body. It would do good to feel fish to check if skin is too slimy or too dry but at least ensure that skin is free of spots and odd bumps and that gills are red. There should be no redness in anal region and definitely nothing sticking out or leaking out. The outside of mouth should be free from redness and white strings and eyes free from white flecks.

• Bag ‘em right. Where you’re buying goldfish, you will have to put them in ubiquitous plastic bag, but do so with care. Make sure that dealer leaves enough space on top for oxygen and right amount of water. The right amount of water is that which covers fish. Do not allow dealer to add any medicine or drops or anything else. Don’t make bag too tight and avoid a big bag that might lead to too many folds in which fish could get trapped and hurt. The bag should be tied till it is adequately taut.