I have an aquarium with about 15 fish, a snail, four frogs. How often should I change the filter cartridge?

My aquarium is a 20-gallon. Among the fish are two catfish. Do you think one snail is enough? The pet store owner (the husband of a close friend) told me to change the filter monthly. Is there any condition under which it should be changed more frequently?|||What kind of filter is it and what kind of fish do you have?





I never change my filter media I just rinse it in tank water once a month. It's best to do it when you are doing your weekly water change. When you toss out the filter media you are also getting rid of alot of good bacteria|||If the water is getting green, then change it more frequently. Otherwise, no. It will be good ;-)|||Hi s.,


Fifteen fish and four frogs in a 20-gallon tank is pretty full unless the fish are smallish tetras. I'd recommend doing partial water changes of 25 percent each week and using the tank's water to clean the filter's cartridge(s). My filter's output slows in a week and so I clean the cartridges weekly or bi-monthly. It won't hurt to clean the cartridges frequently as long as you use the aquarium's water.


I change the filter's cartridges only when they are well used and have broken down to where the filtering efficiency is compromised. And when you change cartridges (if there's more than one) only replace one at a time, with a couple of weeks interval minimum, or you'll be eliminating a high percentage of the biofilter, which can cause potentially harmful ammonia or nitrite spikes.





Regards,


David|||if you over feed and there are lots of unwanted things in the tank, one time we bought a fish that had a rock in the bag, turned out that it was covered with snail eggs, we didnt change the water and filter and in 1 week we had 15 snails eating everything