So now that you’ve finally managed to get your fish to breed, the hard part is over – right? Unfortunately it’s never that simple with fish, and now that the eggs have hatched, you not only have to provide them with nearly perfect water conditions – you also have to feed them.
And feeding them isn’t going to be easy. Unless the fry are live bearer fish, their mouths will be far too tiny to eat any flake or pellet foods you are likely to have on hand. So you’re going to need to buy some food specifically for the fry. The good news is that there is a wide variety of food types to choose from, and many stores now offer food specifically designed for fry.
Brine Shrimp – Hands down the best food to feed to fry are baby brine shrimp. Brine shrimp have long been a staple of the aquarium hobby, and are jammed packed with nutrients and protein vital to fry. Even more important, is that their movements through the water trigger the hunting instinct in baby fish, and even the most finicky of fry will accept them.
Another plus, is that they are extremely easy to culture, and the eggs can be kept for years in a cool, dry place. These eggs can then be hatched in a brine shrimp hatchery, and will be ready to feed to new born fry within 24 to 48 hours. If you want to feed your fry baby brine shrimp, you can find a brine shrimp hatchery at Amazon.com.
Infusoria – Infusoria is a term that refers to all of the tiny creatures that naturally occur in an established aquarium. Most are nearly invisible to the naked eye, and any fish tank with live plants will already have a significant number of them. But even in a planted tank, there won’t be enough to sustain anything but just a few tiny fry, so you will have to supplement their numbers.
Thankfully, it’s incredibly easy to culture infusoria, and to start with, simply fill a bottle with aged aquarium water. Next drop in some fish food and a single lettuce leaf and place the bottle in a sunny spot for about a week.
After a week has passed, the water should be cloudy from a bacterial bloom. Infusoria should start to appear over the next few days, and the water will clear up and take on almost a pinkish tone as they feed on the bacteria. When the water has cleared up, you can start feeding small amounts of this water to you fry.
Green Water– Green water is exactly what it sounds like – water that has turned green from algae growth. Green water is accepted by many different types of fry, but is especially important to herbivore fry that require plant matter in their diet.
To culture green water, place algae scrapings from your tank (grass clippings can be substituted for algae) in a large jar or container filled with treated water. Then place the jar in a sunny spot for about a week, and the water will quickly become choked with algae. To ensure that the algae isn’t just confined to the sides of the jar, you should stir the water every other day to help distribute the algae through the water column.
Once the water has become almost opaque with algae, you can start adding small amounts to the fry tank as needed. You can top up any water taken with treated water, so that the culture continues to renew itself. If you find yourself needing more green water than you are producing, you can start new cultures with a bit of water taken from the original culture.
Egg Yolk – Egg yolk is one of the oldest fry foods, and was popular before most other fry foods became widely available. That’s not to say that egg yolk doesn’t compare to the others in nutritional content, but it is messier and to a certain extent – more annoying.
To feed egg yolk to newborn fry, it should be placed in a non-toxic material with numerous tiny openings. Some people use sterile gauze, while others use nylon. The key is to find a material that can be wrapped around the egg yolk, and allow for a small amount to be squeezed out so the fry can nibble on it.
There is a fair bit of disagreement about where it should be placed in an aquarium, but I find the best way to deliver the food to the fry is to hang it from the side of the aquarium, and allow it to sink about halfway down. The fry can then easily feed on it from this height, and this tends to work with most species of fish fry.
It is important to remove and replace the egg yolk at least every other day, and it may be best to replace the egg yolk every day. If you leave it in the aquarium for too long, it can foul the water, which is usually enough to kill off any fry in the tank.
Prepared Foods – In recent years, numerous prepared fry foods have been introduced to the market. And for the most part, they all make excellent alternatives to spending hours culturing live foods, or adding messy eggs yolks to your fry tanks.
With that being said, there is a huge difference in quality between the different brands of food, and if possible, you should always stick with proven brands like Hikari. I personally use either New Life Spectrum Small Fry Starter Formula or Hikari First Bites with excellent results.
Of course there are downsides to prepared foods, and the main one is it may not trigger a fry’s hunting instinct. If they don’t recognize it as prey, it may take them a while to figure out that it is edible.
So until you know for sure that your fry will accept it, you may want to have a small backup live food culture going – and even then, you may not want to risk it with a hard to breed fish.
Other Live foods – There are numerous other lives foods that work for fry, but most others are either too rare (i.e. banana worms), or are too difficult to breed to be of any use. If you do have access to other small live food, it’s often worth it to offer it to any new-born fry, but always have a back up option in case it doesn’t work for one reason or another.
And a word of caution – never add a live food that you aren’t sure can be eaten by fish fry. There are many live foods that will actively hunt baby fish, but are happily gobbled up by adult fish.