Could use some input - Page 2 - Tropical Fish Keeping - Aquarium fish care and resources
LinkBack Thread Tools
post #11 of 12 Old 03-13-2011, 06:16 PM
Byron's Avatar
Originally Posted by DKRST View Post
During darkness, plants respire by taking in oxygen from their environment for cellular respiration. If a tank is very heavily planted with minimal surface agitation, the oxygen levels can drop significantly during nighttime hours and CO2 levels will increase. The statement that oxygen can never be low in a planted tank is not, biologically, quite accurate. If you found your fish at the surface in the early morning, before the lights are on, I'd recommend turning on some additional agitation at nighttime to increase the oxygen levels and, just as importantly(!), drive off excess CO2. Having said this, it's does not seem to be a typical problem for folks who don't use pressurized CO2.
I did qualify my statement with the words "provided all this is in balance" though perhaps it should have been explained more to be clear. Provided there is a biological equilibrium in the tank, with fish, plants, bacteria in balance, and with a natural method (no CO2 addition) there will never be an oxygen shortage that is detrimental to fish, plants or bacteria. The plants produce far more oxygen during photosynthesis than the fish and bacteria will consume during daylight; and during darkness the majority of fish are resting and thus consuming very minimal oxygen compared to daylight. With this correction, I agree with the rest cited.

Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]
Byron is offline  
Sponsored Links
post #12 of 12 Old 03-13-2011, 06:43 PM
DKRST's Avatar
Byron, I wasn't disputing anything you said, but Kymmie had a similar problem a short while ago and it appeared to be plant and night-time CO2/O2 related after all was said and done.
DKRST is offline  

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Similar Threads
Thread Thread Starter Forum Replies Last Post
Stocking Input Peanut72 Beginner Freshwater Aquarium 8 09-23-2010 10:19 PM
I'm bad, need some input mrdemin Freshwater and Tropical Fish 7 11-20-2009 03:40 PM
Need Your Input jones57742 Cyprinids and Atherinids 18 07-30-2007 12:20 PM

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome