# Water changes and aquarium size.



## neonk (Jun 15, 2012)

I ran a 10 gallon tank succesfully for years on 20% water changes monthly. I only had small fish (neon tetras) and an aquarium crab though. So generally speaking in a tank half the size with similar stocking should the water changes be increased? How does this work?:shock:


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## Sanguinefox (Nov 29, 2011)

neonk said:


> I ran a 10 gallon tank succesfully for years on 20% water changes monthly. I only had small fish (neon tetras) and an aquarium crab though. So generally speaking in a tank half the size with similar stocking should the water changes be increased? How does this work?:shock:


Sounds strange doesn't it? The way it works though is quite simple. Larger tanks have more stable environments. Smaller tanks don't. Though that's not quite the case here.

If you have lets say X fish in 10 gallon they are putting out (insert amount of waste) into ten gallons of water.

Now imagine you take the same X fish and put them in a five gallon. Now they are still putting out (insert amount of waste). Your water is now taking in across five gallons what used to go into 10 gallons. The water gets more dirty faster. Thus you have to do water changes more often (or potentially more water per water change). Smaller tanks reach their limit's water wise faster than bigger ones. It's why smaller tanks are actually often more difficult to keep going versus larger ones.


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## Tazman (Jan 15, 2012)

fish also give off chemicals to attract potential mates and deter predators, these are also removed in water changes.


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## neonk (Jun 15, 2012)

I forgot to add that the ratio of fish to water will be the same, so I will have half the amount of fish as I did in the 10 gallon. Will the 5 gallon still require more water changes just because it is smaller?


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## Sanguinefox (Nov 29, 2011)

neonk said:


> I forgot to add that the ratio of fish to water will be the same, so I will have half the amount of fish as I did in the 10 gallon. Will the 5 gallon still require more water changes just because it is smaller?


What fish are you planning to put in there? A five gallon really doesn't hold much to begin with.


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## neonk (Jun 15, 2012)

Either a couple of neons or some catfish


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## Sanguinefox (Nov 29, 2011)

neonk said:


> Either a couple of neons or some catfish


Cat fish? What specific species?


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## Tazman (Jan 15, 2012)

None in a 5g tank...


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## neonk (Jun 15, 2012)

Smaller ones like corys


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## Tazman (Jan 15, 2012)

Tank is too small for any catfish..sorry.


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## Sanguinefox (Nov 29, 2011)

neonk said:


> Smaller ones like corys


Yeah, don't do it. I could be wrong on this but there isn't a species out there that can survive in such a tank. What specific tetras were you looking at putting in there?


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## neonk (Jun 15, 2012)

Neon tetras, main concern is will the water need changing more just because the tank is smaller.


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## Tazman (Jan 15, 2012)

If you have very very light stocking and test the water regularly then you might be able to get away with slightly less water changes.

The fact the tank is small though will likely mean you will need to change the water possibly once or even twice a week.


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## neonk (Jun 15, 2012)

Thanks,
Logic was telling me If a 5 gallon was lightly stocked, I should be fine. I'm getting the message though that it will require more changes. I should restart the 10 gallon. liked the 5 gallon though, just don't have alot of room, thanks for the replies.


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## Tazman (Jan 15, 2012)

Basically the smaller the tank the more water changes need to be done as there is less volume of water to dilute pollutants.

A good thing to remember - *The solution to Pollution is Dilution* meaning more water changes.

10g would be better off if you can fit it in.


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## Geomancer (Aug 23, 2010)

I agree. Plus Neon Tetra are a shoaling fish and should not be kept in numbers less than 6. They actually greatly prefer larger shoals as they are a small fish, and they've been geneticaly programed over hundreds of years of evolution that there is safety in numbers.

Almost all small fish are this way, and due to that a 5 gallon isn't suited to much of anything. Personally, I'd only keep a Betta with a couple shrimp or a snail in one that small.


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## Byron (Mar 7, 2009)

Agree, a 5g is not sufficient size for any of the "normal" tetra or cory because they must each be in a group regardless of their individual size.

We have fish profiles, and most fish are included. Second tab from the left in the blue bar across the top; info on numbers, minimum tank size, and other issues are included for each species. If the name is identical in posts as i the profile, it will shade, example Neon Tetra, and you can click the shaded name for that profile.

Byron.


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