stocking rules - again

[New Boy]

I read some guidance by Aquarian this weekend that suggests that you should stock fish at 1 inch per imp gallon for the first six months then step up slowly to 2 inches per gallon. Anyone heard of this – is it accurate? I’ve previously relied on the surface area rule (12 sq inches per inch of fish) and according to this rule my tank will be over-stocked when my fish are full grown but according to the volume rule they’ll be fine (I’m getting a bigger tank anyway but will probably then re-stock the old tank)

Thanks
Andy

 

[andyt_uk]

i have always worked to 30sqcm of surface area per cm of fish body (for tropicals)
volume of water (e.g. gallons) has little effect on the levels of oxygenation.

 

[Eelzor]

The main rule I remember is the length of fish should equal the length of the front of the tank. But this EXCLUDES large cichlids.

 

[aernympha]

ahhhh lots of scarey rules???

 

[CFC]

1" per gallon is a good rough guide for begginers but experienced fishkeepers with the right equipment can boost this to 2" or more. You will learn to know when a tank is overstocked, if the fish are happy, dont look cramped and you can keep the nitrates below 50ppm with a regular maintainance routine then the tank is ok.

 

[New Boy]

Thanks CFC,

...but my next question is....if your tap water runs at just over 50 ppm and you do 15% water changes weekly that will actually slightly increase your nitrate (I have quite a few live plants in my tank) is there anything you can do? I'm in the UK so is there any way to reduce the nitrate of the water without changing the ph, kh, gh etc? RO water is fairly soft I believe....? I do 15% water changes weekly but my nitrate never comes down (never had a problem with nitrite or ammonia though.

 

[Eelzor]

But doesn't nitrate only get created in the tank? I'm not sure if nitrate would come straight out of the tap. If it does, I would like to know that question too.

 

[Alien Anna]

Thanks CFC,

...but my next question is....if your tap water runs at just over 50 ppm and you do 15% water changes weekly that will actually slightly increase your nitrate (I have quite a few live plants in my tank) is there anything you can do? I'm in the UK so is there any way to reduce the nitrate of the water without changing the ph, kh, gh etc? RO water is fairly soft I believe....? I do 15% water changes weekly but my nitrate never comes down (never had a problem with nitrite or ammonia though.

You can do a couple of things:
1. Use nitrazorb in your filter. This is rather expensive but effective.
2. Have lots of fast growing plants.

Other than that you can use RO water or buy yourself a nitrate filter.

 

[New Boy]

From my understanding volume is just as important as surface area - it dictates how many minerals are available for the fish and how quickly the fish pollute the tank. A deep tank with the same height and length dimensions as a shallow tank will also have less problems with territory between bottom/mid/top dwelling fish.

 

[CFC]

But doesn't nitrate only get created in the tank? I'm not sure if nitrate would come straight out of the tap. If it does, I would like to know that question too.

In heavily populated areas tapwater is often high in nitrates, where i live in London the nitrate levels often exceed 60ppm, if that is the case with your tapwater and you dont have algea problems and your fish seem in good health then it is best to set a suitable level that you can realisticly maintain, say under 70ppm.
RO water is neutral (pH 7) and the minerals can be added back to adjust the hardness to suit the specific requirements of your fish, it is a better way to go IMO but can get expensive if you dont have your own unit.
I use RO on my largest tank and in my breeding tanks and spend around £15 a week just on water.