How to Feed Fish Fry in Aquariums

Unlike adult fish, fry cannot tolerate starvation at all! Even minor deprivation will be fatal. They require immediate feeding to survive.

Therefore, right after hatching, we need to feed fry every few hours with micro food like infusoria and rotifers. Starting from the second week, we can gradually introduce larger live foods and increase feeding intervals.

Nature’s Timing: Feeding Fry in the Wild

Newly hatched larvae, having absorbed their yolk sac, enter a critical phase of development and will swiftly die if not fed in a timely manner.

That is why, in nature, fish mostly spawn during the rainy season when water bodies are rich in organic material, providing ample food.

This season brings overflow of water, washing plants, and organic materials into lakes, rivers, ponds, etc. This influx of organic matter helps various organisms grow, providing food for fish. The timing of these tiny food sources and newly hatched fry shows how nature ensures that young fish have:

• plenty to eat,
• constant access,
• nutritious and varied food

Therefore, we need to replicate these feeding conditions (at least partially) in our aquariums.

Commercial Products to Feed Fry

I will start with the simplest solution – specific types of commercial products designed for feeding fry.

Here are some popular commercial products recommended for feeding newly hatched fry and older fry:

1. Hikari First Bites: A finely powdered food designed for newly hatched fry.
2. Sera Micron: It closely resembles natural plankton, promoting healthy growth, a strong immune system, and good coloration without polluting the water.
3. New Life Spectrum Fry Food: Small, floating pellets specially formulated for fry.

Note: Some aquarists also crush regular fish flakes or pellets into a fine powder to create a suitable food for fry.

Of course, there are some other products available on the market for feeding fry. However, if you keep an expensive fish or simply want to create better conditions, it is best to feed fry live food anyway.

Live Food to Feed Fry

I will list live food in order of size, starting with the smallest options suitable for newly hatched fry in their first few days.  As the fry grow, they will need larger foods, keeping in mind that not all fish species can follow the same guidelines.

For Newly Hatched Fry:

In the first week of life, most fry require micro-sized food. If given something larger, they simply will not be able to consume it. So, our choice is pretty limited here.

1. Infusoria (0.004 – 0.012 inches / 100 – 300 micrometers)

Infusoria are tiny, single-celled organisms. They are so small that can be easily eaten by fry that have just started swimming. In nature, they will be among the first foods fry can consume after hatching.

2. Rotifers (0.002 – 0.08 inches / 50 micrometers – 2 mm)

Rotifers are also one of the smallest multicellular organisms. They are small in size and easily digestible. It makes them ideal for the first few days of feeding. They are an excellent first food for newly hatched fry.

For 1-2 Weeks Old Fry:

Once the fry grows a bit larger, along with infusoria and rotifers, we can also begin introducing microworms, vinegar eels, etc. into their diet.

1. Vinegar Eels (0.06 – 0.08 inches / 1.5 – 2 mm)

Vinegar eels are small, free-living nematodes. They are easy to culture and provide a slightly larger food source as the fry grow.

2. Moina (0.008 – 0.02 inches / 0.2 – 0.5 mm)

Moina are tiny crustaceans. They are often used as a live food source for very young fry. Due to their small size, Moina are ideal for fry that have outgrown infusoria but are not yet ready for larger prey like Daphnia.

3. Microworms (0.04 – 0.08 inches / 1 – 2 mm)

Microworms are tiny nematodes. They are slightly larger than infusoria and rotifers, making them suitable for fry after their first week. Microworms are high in protein and fat, which are vital for the growth and energy needs of fry.

4. Ostracods (Seed Shrimp) (0.008 – 0.08 inches / 0.2 – 2 mm)

Ostracods (Seed shrimp) are small aquatic crustaceans with a hard outer shell. Although they can be used as live food there are a few downsides. Firstly, they reproduce pretty slowly. Secondly, they have a moderate nutritional profile, and their hard shell makes the nutrients less accessible to fry.

So in my book, we can use them only in combination with other food sources for optimal feeding results.

5. Cyclops (0.02 – 0.08 inches / 0.5 – 2 mm)

Cyclops are small crustaceans that can be introduced as the fry grow larger, usually after 1 or 2 weeks. Although their chitinous shell is not digested, it can serve as valuable ballast material that stimulates peristalsis in the fry intestine.

As with seed shrimp, it is better to use them only in combination with other food sources.

For Older Fry:

After two weeks, the vast majority of fry across different fish species will have grown significantly and become strong enough to transition to larger-sized food. For worms, I would still give them to the fry in chopped form for now.

1. Daphnia (0.04 – 0.2 inches / 1 – 5 mm)

Daphnia (Water fleas) are aquatic crustaceans with slender bodies and long appendages. They are a common food for growing fry in aquariums. Daphnia are an excellent food source for promoting growth and development.

2. Artemia (Brine Shrimp) (up to 0.6 inches / 1.5 cm)

Brine shrimp (Artemia) nauplii are probably the most popular live food in aquaculture for feeding fry. They are a bit larger than Daphnia and are often introduced as fry mature further.

They are highly rich in protein and fatty acids. It helps in overall health and provides a highly nutritious diet for growing fry.

3. Mosquito Larvae (0.04 – 0.4 inches / 1 mm – 1 cm)

Mosquito larvae will provide a more substantial and satisfying meal as the fry grow. They are also high in protein and fat, making them an excellent food for boosting growth in maturing fry.

4. Grindal Worms (up to 0.6 inches / 1.5 cm)

Grindal worms are small, white worms that are ideal for larger fry. They are easy to culture and provide a nutritious live food option. They contain lots of protein, minimal fat, and carbohydrates with a large amount of vitamin A and carotene. It makes them a healthy and nutritious food option for your fry and small fish.

5. Detritus Worms (up to 0.6 inches / 1.5 cm)

Detritus worms are small, segmented worms often found in aquariums. They can also be used as live food for larger fry.

6. Bloodworms (0.2 – 1 inch / 5 – 25 mm)

Bloodworms  are widely used as live food for larger fry and adult fish. They contain lots of protein with a large amount of vitamins and essential amino acids.

7. Blackworms (0.4 – 2.5 inches / 1 – 6 cm)

Blackworms are small, aquatic worms that can be fed to larger fry and fish. They are a highly nutritious and easily digestible food source for larger fry. They are rich in protein and essential fatty acids.

8. Tubifex Worms (0.2 – 2.3 inches / 0.5 – 6 cm)

Tubifex worms are small, segmented worms commonly used in the aquarium hobby. They are an excellent live food for larger fry and fish. They provide a rich and balanced diet that promotes healthy growth and development.

DIY Fry Foods

If you do not have commercial food or live food, you can try traditional fry feeding methods. These are less effective, coming 3^rd after live and commercial foods, but they are your best option if nothing else is available.

Use it as an emergency food for fry:

1. Boil an egg until the yolk is fully cooked.
2. Take a small piece of the yolk and mash it thoroughly in a spoon with a bit of water from the aquarium.
3. Using a dropper or small spoon, add a few drops of the egg yolk mixture to areas where the fry gather.

Another option is to add a bit of dry milk powder. The powder floats on the surface for about an hour, giving the fry enough time to eat it. Additionally, this method does not spoil water that much and it remains clean even without aeration.

How Often to Feed Fry

In the first days, it is highly recommended to feed the fry every 4-6 hours. After that, you can gradually increase the time between feedings. By 4^th weeks of age, you can reduce feeding to 2-3 times a day.

It is important not to give too much at once. By spreading out small portions throughout the day, you ensure that they always have fresh food available without overloading the rearing tank.

In Conclusion

It is extremely important to give fry proper feeding during their early stages of development. Once fry absorb their yolk sacs, they need constant, nutritious food.

If their diet is not right, it will definitely cause issues in raising them.

While there are good commercial fry foods, numerous experiments have shown that they generally fall short compared to live food. Fry fed with live food tend to have higher survival rates, gain weight, and grow much faster.

Related articles:

• 15+ Live Food Options for Aquarium Fish
• How to Protect Fish Eggs in Your Tank