# floating plant and oxygen levels?



## yhead777 (Jun 4, 2006)

hi guys,

on page 148 of diana's book,
it said that ...ponds with only floating plant often have decreased oxygen levels...

but i put 2xguppy(or 2xtetra, 3xshrimp..) in a 700cc plastic cup noly with water and many floating plants(Pistia stratiotes) , the fish do not show any different (no wheezing).and i do 100% water change everyday, find the fish can live in such environment for many days.

why?


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## gibmaker (Jan 3, 2007)

Every time you do a water change you are introducing more oxygen. There is enough surface area to allow gas exchange for a few small fish


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## flagg (Nov 29, 2004)

I am truly disgusted by this post.

More important than why fish can live in such a small quantity of water covered with floating plants, is a consideration of the complete and total lack of moral and ethical responsibility on your part for keeping tetras or guppies (or most other fish) in such a small volume of water for anything but the shortest amount of time (eg, the amount of time it takes to transport fish). Doing it as some sort of experiment (which appears to be what you're doing) is wholly irresponsible. I would suggest doing some reading on fish husbandry and their requirements before you torture your fish any more. 

-ricardo


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## Tex Gal (Nov 1, 2007)

I do agree that it's not responsible to the fish to keep them in such a small area. What is the point? What are you trying to do? Are you waiting for your tank to cycle, treating them for disease?... You really need to get them in a decent place to live.


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## yhead777 (Jun 4, 2006)

i apologize for what i had done to the fish. 

i mean.... should i notice the oxygen problem when i keep fish in a bare tank just with lot of floating plants(whatevere if there is filter)?

in my country, some people do not keep plant in their aquarium (like discus, asia arowana fans...),
because they think plant is too hard to take care.

i know plant is good in many ways to the auqarium, and the floating is the easier one to keep.
so beside bare tank and planted tank, bare + floating plant tank may be another choice.

ps.
diana's book said that a pond just with floating plants cover,
the oxygen volume is 0.2-3 ppm.
and the limitest of fish need is 2 ppm.


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## dwalstad (Apr 14, 2006)

yhead777 said:


> i apologize for what i had done to the fish.
> 
> i mean.... should i notice the oxygen problem when i keep fish in a bare tank just with lot of floating plants(whatevere if there is filter)?
> 
> ...


Dear Yhead,

I am sorry for your confusion. I appreciate such a dedicated student, but I would not worry.

The example in my book [page 148] is a pond ecosystem that probably does not apply to your situation. The water hyacinths could be doing fine but have some decomposing plants. This decomposition will remove oxygen from the water.

Your ecosystem is probably very different. You are changing water frequently to remove organic matter from the water. Therefore, you may have less bacteria consuming water oxygen.

If your fish are doing well-- have good apetites and have a friend to play with, then I wouldn't worry. Floating plants will probably help cut down on the ammonia and increase biological activity and interest for your fish (lots of little protozoa for them to feed on). I would keep the floating plants.


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## wmsvn (Oct 22, 2008)

> it said that ...ponds with only floating plant often have decreased oxygen levels...


Only true of all the floating plant covered the entire surface of the water which stops the oxygen exchange and light from penetrate into the water which helps other organism in the water.


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