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Body Weight Vs. Bioload Analysis


Erinaceus

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I was just reading on the 'Research submissions' subforum and a thought came to me: it would theoretically be possible to do do some experiments to figure out what the relationship of waste to body weight actually is and, importantly, how it differs between different breed of goldfish. One 'easy' way to do this would be to put a goldfish in a normal sized cycled tank, wait for say a week, and then measure the nitrate level, and repeat this a great many times for different sizes and types of goldfish. The problem here is that it would take a long, loooong time to get a decent sample size. Because the typical method for measuring nitrate levels is rather inaccurate (for scientific purposes), the amount of samples would need to be even larger, to compensate for this.

An alternative method I just thought about would be to use data on tanks with differing compositions of goldfish sizes and types, and to statistically tweak apart the effect of the different sizes and types. This might be doable, if enough people were to share there tank logs.

Any thoughts?

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This could be an interesting study.... however an EXTREMELY difficult one to get beyond soft-science. There are so many varilables - most of which are fairly uncontrolable......

Fish differ - not just between breeds and size. In a group of fish - same spawn, raised in identical conditions - you will find fish that have it all going for them - they grow by leaps and bounds (the "hogs" of the spawn), you will find average fish ("standards") and you will find the "runts".....fish that, for one reason or another do not thrive the same way. It is thought that much of that malaise is caused by incorrecct design of the fish's digestive tract. What one fish can process easily and well, another may do only partially, and still another may stuggle to do at all. These fish cannot be identified by eye..... Your sample numbers would be greatly reduced by sorting though fish to find a set of "average" ones representlng specific breeds.

Feeding. Even within a commercially produced food, there is great variences in the actual protien/carbohydrate/fat content of the food. There is an allowed "slop" of exact composition that is built in - in some cases it is many percentages. Some brands have less slop, others have significant. Considering the average food supplier for cat/dog food is only required to test food conformity once a year, I would have to assume that fish food is no better. It would be, therefore, very hard to judge the food equality between samples. Better done with all fresh produced food - done in the "lab".

Water temperature, water flow (dirty filter or clean - in a full or sparcely stocked tank - big differences), pH, kH all affect the viability and efficiancy of the beneficial bacteria that make up the nitrogen cycle. You would even have to standardize the oxygen input into a tank - from air bubblers that lift the water to lids..... Light duration and algae growth would be a consideration.

I realize that I am very VERY compulsive when it comes to designing experiments. Not only do I do this for a living in many aspects, but I also am a judge for many science fairs and scholarship competitions. I get pretty picky - far too, perhaps, for the answers needed on this one.

It could be a very interesting study - and, depending on your control of variables - actually very informative. If I can help in any way, let me know. I keep very accurate records of tanks and such - just not weights of fish. That I keep "by eyeball" - very unscientific!

:)

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This could be an interesting study.... however an EXTREMELY difficult one to get beyond soft-science. There are so many varilables - most of which are fairly uncontrolable......

Fish differ - not just between breeds and size. In a group of fish - same spawn, raised in identical conditions - you will find fish that have it all going for them - they grow by leaps and bounds (the "hogs" of the spawn), you will find average fish ("standards") and you will find the "runts".....fish that, for one reason or another do not thrive the same way. It is thought that much of that malaise is caused by incorrecct design of the fish's digestive tract. What one fish can process easily and well, another may do only partially, and still another may stuggle to do at all. These fish cannot be identified by eye..... Your sample numbers would be greatly reduced by sorting though fish to find a set of "average" ones representlng specific breeds.

Feeding. Even within a commercially produced food, there is great variences in the actual protien/carbohydrate/fat content of the food. There is an allowed "slop" of exact composition that is built in - in some cases it is many percentages. Some brands have less slop, others have significant. Considering the average food supplier for cat/dog food is only required to test food conformity once a year, I would have to assume that fish food is no better. It would be, therefore, very hard to judge the food equality between samples. Better done with all fresh produced food - done in the "lab".

Water temperature, water flow (dirty filter or clean - in a full or sparcely stocked tank - big differences), pH, kH all affect the viability and efficiancy of the beneficial bacteria that make up the nitrogen cycle. You would even have to standardize the oxygen input into a tank - from air bubblers that lift the water to lids..... Light duration and algae growth would be a consideration.

I realize that I am very VERY compulsive when it comes to designing experiments. Not only do I do this for a living in many aspects, but I also am a judge for many science fairs and scholarship competitions. I get pretty picky - far too, perhaps, for the answers needed on this one.

It could be a very interesting study - and, depending on your control of variables - actually very informative. If I can help in any way, let me know. I keep very accurate records of tanks and such - just not weights of fish. That I keep "by eyeball" - very unscientific!

:)

Yeah, I didn't mean it to be anything 'publishable', but just as a wet-thumb kind of study (calling it a pilot would be stretching the term a bit) to get at least some idea :) . What you mentioned about fish differing, I would think that weight vs age would at least partly control for this type of effects. The food differences hadn't occurred to me, and given that uneated food (if possible in a goldfish tank) can also result in ammonia (IIRC) it would indeed be hard to control for that (if not impossible). The cycle differences I think would be less of an issue (in the sense that you get nitrates = F(ammonia) no matter what time frame it occurs in, I'd think; evaporation?), but algae activity would indeed be rather hard to control for.

I'd prefer to do it by getting 10 identical 10-15 gallons tanks (for parelleling purposes), keep a goldfish in each of them for say a week and then measure the nitrates. After that week, clean the tank thoroughly to get rid of any algae (maybe after allowing the tank to continue to cycle for a few days if there's still trace amount of ammonia present). If I were to repeat that for say 20 runs (->20x10 goldfish) and them repeat it again after 6 months, 1 year and 2 years, I'd be able to uses a repeated measures test to look at the same fish for different ages (thus seeing how waste producing increases with age), then look at how weight influences this curve regardless of age, and finally use the added variation in morphology to get an idea of differences between breeds (but I'd rather use measures like wen size, telescope eye length, and other measures that differ between breeds, rather than use breeds as discrete categories).

It's a nice day dream of an experiment, but not feasible - at least not before my retirement in 40 years or so :rofl .

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This could be an interesting study.... however an EXTREMELY difficult one to get beyond soft-science. There are so many varilables - most of which are fairly uncontrolable......

Fish differ - not just between breeds and size. In a group of fish - same spawn, raised in identical conditions - you will find fish that have it all going for them - they grow by leaps and bounds (the "hogs" of the spawn), you will find average fish ("standards") and you will find the "runts".....fish that, for one reason or another do not thrive the same way. It is thought that much of that malaise is caused by incorrecct design of the fish's digestive tract. What one fish can process easily and well, another may do only partially, and still another may stuggle to do at all. These fish cannot be identified by eye..... Your sample numbers would be greatly reduced by sorting though fish to find a set of "average" ones representlng specific breeds.

Feeding. Even within a commercially produced food, there is great variences in the actual protien/carbohydrate/fat content of the food. There is an allowed "slop" of exact composition that is built in - in some cases it is many percentages. Some brands have less slop, others have significant. Considering the average food supplier for cat/dog food is only required to test food conformity once a year, I would have to assume that fish food is no better. It would be, therefore, very hard to judge the food equality between samples. Better done with all fresh produced food - done in the "lab".

Water temperature, water flow (dirty filter or clean - in a full or sparcely stocked tank - big differences), pH, kH all affect the viability and efficiancy of the beneficial bacteria that make up the nitrogen cycle. You would even have to standardize the oxygen input into a tank - from air bubblers that lift the water to lids..... Light duration and algae growth would be a consideration.

I realize that I am very VERY compulsive when it comes to designing experiments. Not only do I do this for a living in many aspects, but I also am a judge for many science fairs and scholarship competitions. I get pretty picky - far too, perhaps, for the answers needed on this one.

It could be a very interesting study - and, depending on your control of variables - actually very informative. If I can help in any way, let me know. I keep very accurate records of tanks and such - just not weights of fish. That I keep "by eyeball" - very unscientific!

:)

Yeah, I didn't mean it to be anything 'publishable', but just as a wet-thumb kind of study (calling it a pilot would be stretching the term a bit) to get at least some idea :) . What you mentioned about fish differing, I would think that weight vs age would at least partly control for this type of effects. The food differences hadn't occurred to me, and given that uneated food (if possible in a goldfish tank) can also result in ammonia (IIRC) it would indeed be hard to control for that (if not impossible). The cycle differences I think would be less of an issue (in the sense that you get nitrates = F(ammonia) no matter what time frame it occurs in, I'd think; evaporation?), but algae activity would indeed be rather hard to control for.

I'd prefer to do it by getting 10 identical 10-15 gallons tanks (for parelleling purposes), keep a goldfish in each of them for say a week and then measure the nitrates. After that week, clean the tank thoroughly to get rid of any algae (maybe after allowing the tank to continue to cycle for a few days if there's still trace amount of ammonia present). If I were to repeat that for say 20 runs (->20x10 goldfish) and them repeat it again after 6 months, 1 year and 2 years, I'd be able to uses a repeated measures test to look at the same fish for different ages (thus seeing how waste producing increases with age), then look at how weight influences this curve regardless of age, and finally use the added variation in morphology to get an idea of differences between breeds (but I'd rather use measures like wen size, telescope eye length, and other measures that differ between breeds, rather than use breeds as discrete categories).

It's a nice day dream of an experiment, but not feasible - at least not before my retirement in 40 years or so :rofl .

I am not doing w/c on that set-up, as it is your project :rofl

You will need a fish room for such a big set up, as in a tab and a drain very close to the tanks are it seems just not doable else way.

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Cool idea!

I think you could take care of the food issue by making a very large batch of well mixed gel food. As long as you know that all the fish are eating the same thing the results will be comparable.

My first thought was filtration. As you said, the tanks would be cycled, but I'm thinking it'd be basically impossible to maintain the same levels of bb in all the filters. I guess you'd have to run the tanks on a centralized filtration system like they have at some lfs's.

I'm willing to bet that if you really dug, you'd find some method that's been developed for this sort of thing for aquaculture research :)

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Guest Danicole

BUT if it was on a centralized filter, wouldn't the water be cycling between the tanks? If the goal was to see which fish produced the most weight, wouldn't that defeat the purpose?

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BUT if it was on a centralized filter, wouldn't the water be cycling between the tanks? If the goal was to see which fish produced the most weight, wouldn't that defeat the purpose?

:rofl YES! Did I mention I'm an aquatic biologist....... :donthit:

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BUT if it was on a centralized filter, wouldn't the water be cycling between the tanks? If the goal was to see which fish produced the most weight, wouldn't that defeat the purpose?

:rofl YES! Did I mention I'm an aquatic biologist....... :donthit:

You are forgiven :D

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I'm just gonna let all you mad scientists talk amongst yourselves! lol! :rofl

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Guest Isilme

I think the idea of a cycled tank just adds another uncontrolled variable... The cycling-bacteria's efficiency and numbers can differ between filters and you can't control that. Maybe it would be better to put fish in containers without filter and monitor the ammonia level on a minute-basis for a period of time untill you see the ammonia concentration become hazardous. Then you can calculate the slope of the graph of the speed ammonia is produces and the time it takes before hazardous concentrations occur. Fish should be places in similar containers with same water etc. and should be fed the same diet (grams and mix) for a few days. Maybe they should also be fasted 1 day or more days prior to the experiment. Ammonia can be easily measured (not at home, but we have the machine in the lab next to me,... MIRA, I :heart you! ;) ).

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Guest Isilme

Just found an article: A bioenergetic model to estimate feed requirement of gibel carp, Carassius auratus gibelio, Author(s): Zhou ZG, Xie SQ, Lei W, Zhu XM, Yang YX, Aquaculture 2005 (248): 287-297.

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Just found an article: A bioenergetic model to estimate feed requirement of gibel carp, Carassius auratus gibelio, Author(s): Zhou ZG, Xie SQ, Lei W, Zhu XM, Yang YX, Aquaculture 2005 (248): 287-297.

I skimmed through it and it seems interesting. I'll have a better look at home :) . (thank's for the search/find, Isilme ;) )

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