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Water change frequency and stocking question

3K views 7 replies 4 participants last post by  1077 
#1 ·
First off let me say how much I appreciate this forum. You have helped me set up my aquarium which i thoroughly enjoy. Without the help of this forum it would have been much more difficult to select plants, fish types, etc, and I would have probably accidentally hurt some fish :(.

My tank has had fish in it now for a couple months, and I have never had any NH3 or NO2 and only one fish death (a bullied Gourami).

I have a 20 gallon tank with the following:

3 dwarf Gouramis
3 hatchetfish
5 neon tetra
4 cories
1 snail
3 plants, a very large one that covers half of the back, and two smaller ones

First question:

I would love to add 3 more hatchetfish, 5 more neons and a couple more cories, but I fear this may result in overstocking. I would love your thoughts.

Second question:

I am wondering how often and how much water I should change. I have been changing the water very infrequently (5% each month) because I test the Nitrate and it has never gone over 10 ppm. My understanding is that this is ok, but I have been told by others that the fish poo that accumulates in the bottom can be harmful, and that I should change it more. What do you think about this?

Thanks for your help!
 
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#2 ·
If I were you, I would not add any more fish as you are pretty much stocked. I do a partial water change weekly of about 15-20% but no less than 10% and I have a 35 gal tank. If you were to add more fish, you would definitely need to up your frequency of water changes. Lets see what everyone else says about it. Good Luck.
 
#5 ·
I would maybe consider getting a larger tank before I purchased any more fish. I believe your tank is WELL stocked= At capacity. Weekly water changes will always benefit the fish.
 
#6 ·
I agree that you are at stocking capacity. Weekly water changes are healthier for your fish. I do weekly water changes of about 25-30%. In my opinion, 5% once a month is not nearly enough.
 
#7 ·
Thanks for the help, I will do more water changes for sure. I am curious as to the reason why more changes are required. What aspect of the water quality deteriorates, and is improved by a water change?

Also, my tap water is at pH 7.8 and my tank is at 6.8. I brought the ph down with a piece of driftwood and a tiny bit of peat in the filter (which I have since removed), as advised by my LFS. When I do water changes, what action, if any, should I take to make the new water the same pH? I could swish a little peat around in there, or should i just leave it?

As for adding water lost due to evaporation, I have the same question as above. Should I use some peat to drop the pH?
 
#8 ·
Water changes dilute toxins such as ammonia and nitrites which even at small levels can kill fish. This becomes even more important in smaller tanks with less volume of water than larger tanks. Water changes along with vaccuming the substrate (gravel) will remove dissolved organics,fish waste, and uneaten food that filter cannot. Filter can only remove suspended particulates in the water. Water changes also restore trace minerals that fish need like calcium,and magnesium. Those same minerals help buffer the ph to prevent fluctuations which are also harmful to fish.
I agree with the person who told you that lowering your ph was not needed. All of the fish you listed would ,will do fine with the tapwater you have. To prevent pH fluctuations during water changes,, I would drop the 25 percent water changes to 10 percent every couple days with tapwater and dechlorinator. The 6.8 pH in your tank helps keep ammonia at less toxic levels and sudden change in pH by performing large water change or changes would in my view,be extremely stressful for the fish. If you perform small ten percent changes every couple days then the water in your tank over a period of a week or two ,should more closely match the tapwater you have and from that point,, Weekly 25 percent water change would be sufficient along with not overfeeding, or adding anymore fish. I would use a dechlorinator such as PRIME for the water changes were it me. hope some of this helps.
 
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