Would you love to help your fish fry grow faster? Instead of buying nutritious microorganisms called infusoria, make your own with a little leftover produce. Combine a few pieces of leafy greens or vegetables in a jar with water from an established tank. Then leave it in the sunshine so the produce makes bacteria for the infusoria to feed on. Use an eye dropper to feed your fish fry a few drops of water that are rich with the infusoria and watch them grow!
Choose vegetables to make the infusoria starter. You can use canned or fresh vegetables as the base for the infusoria. If you like, use more than 1 type of vegetable, which will encourage a variety of microorganisms to grow. Consider using:
Fill a 1 US quart (950 ml) jar 1/4 full with the vegetables. Chop the leafy greens into 1 to 2 inches (2.5 to 5.1 cm) pieces before you put them into the jar and shell green beans or peas. Put both the shells of the green beans and the peas into the jar.
Fill the jar 1/3 full with boiling water and let it cool for 5 minutes. Bring a kettle of water to boil and carefully pour boiling water over the vegetables in the jar. Pour slowly until the jar is 1/3 full with boiling water. Then let the water cool until it’s simply warm.
Pour in aquarium water to fill the jar. Once the water in the jar is just warm to the touch, slowly pour in water from an established aquarium. Keep pouring until the jar is full of water.
Set the jar in a sunny place near a window. Move the jar to a windowsill where it will get sunshine throughout the day. While you don’t need to seal the jar shut, you can place a light cloth, such as cheesecloth, over the top to prevent things from falling into the jar.
Wait 2 to 3 days for the infusoria to develop. You’ll notice the water become cloudy, which means that bacteria is starting to grow. As the infusoria grow, the water will become clearer because the infusoria is feeding on the bacteria. This is how you know the infusoria is ready to feed to your fish fry.
Tip: If you see scum form at the top of water, swirl the jar gently. This will ensure that oxygen reaches the material down in the jar.
Use the dropper to feed the fry a few drops of infusoria twice a day. Insert a clean eye dropper or turkey baster into the middle of the jar with the infusoria. Remove some of the liquid and squirt a few drops into the fish tank that has your fry in it. Since the fry are growing quickly, feed them infusoria at least 2 times a day.
Feed the fry infusoria for about 1 week. Continue to feed the infusoria to your fish fry until they’re big enough to start eating larger foods, such as brine shrimp nauplii. You should see the fry develop and grow quickly.
Tip: If you’d like to have a batch of infusoria ready for when you discard your initial batch, start a new jar 3 to 4 days after starting the first.
Store the infusoria at room temperature. Keep the infusoria alive by avoiding extreme swings in temperature. Instead of storing the jar of infusoria in the refrigerator, leave it at room temperature. To slow down the development of bacteria and infusoria, remove the jar from the window and put it on a counter out of direct sunlight.
Discard the infusoria after 2 days. Once the infusoria has developed enough to feed to your fish fry, plan on using it within 2 days. After 2 days, the infusoria won’t develop and bacteria will overwhelm the jar. This will make the water cloudy again. You’ll also notice a rotting smell coming from the produce in the jar.