Now that you have 5000 answers telling you 5000 different things, here’s one more

Yes, the general rule is 20-25 % every week but there is some leeway in this. You need to test the water and see how much ammonia is being produced and if you are having pH drops. If your tank cannot handle the bioload, then more drastic measures are called for, if everything is perfect (never happens) then not so much. It is theoretically possible to have enough natural filtration from a heavily planted tank to only need to replace water from evaporation. This requires a virtually self contained environment, not many people have been able to do it properly. That is an exception. Most tanks require the weekly or bi-weekly water changes to keep them healthy.

How much water/waste you need to remove will depend upon how your water quality is. If your Ammonia and Nitrites stay at 0 ppm and your Nitrates under 40 ppm and you do not have any pH drops, then you should be fine with 20% every other week. If this is not the case, adjust water changes up (probably 25% every week) until you have the right water parameters.

do 20% water change everyweek

A cichlid needs to something besides live guppies, try some good cichlid pellets too. A 25% water change every 2 weeks and a 50% water change every 2 months. MAke sure you have a really good filtration system running 24/7/365.

30% water change every week. Can’t go wrong. (also use a gravel vacuum to suck up all his poo on the bottom)

Only if the water starts to look merky. You don’t want to disturb the little guys if not necessary. Your filter should be checked fairly often and when it looks dirty, change it. Use a sponge (from pet store) to clean any algae of glass. It’s good to keep some Algae Eaters in the tank, say two per 10 gallon tank. They will clean the glass for you

Every 3 weeks or so, change 25% or so of the water in the tank. Every so often use those magnetic cleaners that go two ways along the glass, cleans the glass.

When you see the fish get the shovels out… Tee hee hee,,,just kidding.

if you have time you you should clean leaving every three or four days bcoz contaminated water may be harmful to the fishes

You should change about 25% of the water once a week and use a gravel siphon to clean the gravel as you remove the water. If this fish is very dirty or the filter isn’t keeping much of the waste out of the tank, you should probably change 35-40% of the water once a week.

MM

On average clean about 25% of the water each month with a gravel syphon. You might want to clean it more often since you are feeding live food.