Dissolved Oxygen
Embed This Widget
Add the script tag and a data attribute to embed this widget.
<script src="https://cdn.jsdelivr.net/npm/fishfyi-embed@1/dist/embed.min.js" defer></script>
<div data-fishfyi="glossary" data-slug="dissolved-oxygen"></div>Embed via iframe for maximum compatibility.
<iframe src="https://fishfyi.com/iframe/glossary/dissolved-oxygen/" width="420" height="400" frameborder="0" style="border:0;border-radius:10px;max-width:100%" loading="lazy"></iframe>Paste this URL in WordPress, Medium, or any oEmbed-compatible platform.
https://fishfyi.com/glossary/dissolved-oxygen/Add a dynamic SVG badge to your README or docs.
[](https://fishfyi.com/glossary/dissolved-oxygen/)Use the native HTML custom element.
<script src="https://cdn.jsdelivr.net/npm/fishfyi-embed@1/dist/embed.min.js" defer></script>
<fishfyi-glossary slug="dissolved-oxygen"></fishfyi-glossary>Définition
The amount of oxygen gas dissolved in water, critical for fish survival. Warm water holds less oxygen than cold water, and low levels cause fish stress and mortality.
Explication détaillée
Dissolved oxygen (DO) in water at saturation is 14.6 mg/L at 0 °C and only 7.6 mg/L at 30 °C — a near-halving that explains why warm-water fish kills are common in summer. Fish behavioral responses to hypoxia include surface skimming (aquatic surface respiration), reduced activity, and habitat abandonment. Obligate air-breathing fish (labyrinth fish, lungfish) tolerate near-zero DO. Oxygen requirements vary by species: cold-water salmonids require >7 mg/L while warm-water catfish tolerate <2 mg/L. Nighttime DO dips in heavily vegetated waters as plants switch from oxygen production to respiration can cause dawn fish kills even in otherwise healthy systems.