The concern is not with the removal of bacteria with a drastic water change, but with the resulting drastic change in water chemistry. Fish can die after a large water change due to such things as drastic alteration in pH. Why would this not also negatively affect our unicellular organisms in the tank, i.e. beneficial bacteria?
Question regarding water changes
- Thread starter platytetrafan
- Start date
If you are performing 50-75% water changes every single day, like you said, I bet you don’t even need beneficial bacteria or even have a cycled tank! The nitrogenous compounds would never build up. Ha, ha, More power to you!
That was for juvenile fish but as they became adult size I still fed 2-3 x/day. That creates a lot of waste & my minimum WCs were 3-5 times/week, 40 -80%. Discus, in addition to liking several small meals/day , shed a slime coat that needs to be kept in check or it's like a brown coating over glass & decor.
5-6x a day is because they are growing fish that grow relatively fast and growth rates are determined by the amount of clean water and energy source ,i.e food. But when you feed that much the will be a elevated constant level of wastes being outputted due to food running through the fish at almost all times.
Beneficial bacteria will form anyways. If you do do 50% water changes a day, ammonia will still build up. Say you have a tank that is stocked that produces .5 ppm of ammonia daily. You do a WC and that makes it .25, and then .5 is produced making .75, repeat.
Your logic is under the assumption that there is no conversion of the ammonia to nitrites, which is not the case.
ptfan, if you fish aren't too stunted, you may help them grow with lots of water changes & several small meals/day. They can sometimes recover some more normal growth. Do the best you can...
But the fish produce ammonia which is translated into nitrate, and that builds up, which can get toxic if exposed in high conditions long term.
