We have developed and manufactured this re-usable 24-well glass microtiter plate for high through-put respiration measurements in tiny aquatic organisms like zebrafish embryos, Daphnia, fish/invert eggs or larvae, Drosophila etc. Individual organisms are placed inside gas-tight 80-1700 µl glass chambers sealed with an impermeable PCR film for real-time oxygen consumption rate measurements. The glass material provides non-permeable surfaces, unlike ordinary well plates that are made of gas permeable plastics. Each well is fitted with an oxygen sensor spot allowing for non-invasive optical oxygen measurements when placing the microplate on a special reader. The glass microplate and sensor spots can be cleaned with chlorine, ethanol etc. between trials and re-calibrated and thus used again and again.