Why 250 Fish in Your Pond Could Be a Disaster (Or Perfectly Fine)
Calculate your pond’s volume by measuring length times width times average depth, then multiply by 7.5 to get gallons. This tells you if your 250 fish are comfortably housed or dangerously overcrowded. A standard rule suggests one inch of fish per 10 gallons of water, so 250 six-inch koi would need at least 15,000 gallons, while 250 three-inch goldfish could thrive in 7,500 gallons.
Test your water weekly for ammonia, nitrite, and nitrate levels using a simple liquid test kit from any pet store. Ammonia above 0.25 ppm or nitrite above 0.5 ppm signals overcrowding stress, meaning your biological filter can’t handle the …










