Home | Aquarium Livestock | Spawning Fish in the Aquarium – Raising Fry

Spawning Fish in the Aquarium – Raising Fry

Baby AcaraIf you have a healthy, well-established aquarium and happy fish, there is a good possibility that you may be blessed with batches of eggs or baby fish from time to time.  A common question our customers pose is “What do I have to do for them?” That’s a question that can have several different answers. As with most things aquarium, the first things to consider are your set up and the fish in concern.

Nature’s Course

The most passive answer is “do nothing”. It may not be the answer you want to hear, but depending on your situation, it may be the best one. Some fish are naturally attentive parents. They may actively defend and even nurture the fry their brood. As long as the threats within the tank are minimal (few if any predators, low flow, ect.) and the small fish have plenty of cover, they will have a chance.  A few of of the offspring may survive to maturity, but most will disappear, just as it happens in the wild.

If you choose to allow fate to take it’s course, there are a few things you can do that may increase their chances. Regular maintenance of the aquarium to keep the water quality pristine is a must, of course, it’s important to all of the fish in the tank, not just the babies. Just be a little more careful in the routine, especially when vacuuming your substrate, as tiny fish may be hiding between pebbles. The addition of a few additional live or plastic plants will be appreciated as cover. Look for varieties with small leaves or bushy growth habits. Hornwort, anacharis, cabomba, and similar bunches plants are good candidates, as are plastic “breeding grass” clusters. You may also consider adjusting the flow in the aquarium if possible and applying simple prefilters to intakes so the fry don’t get sucked into the filter.

So You Want to Adopt Some Fish Fry

If you decide you’d like to try to raise as many of the new babies to viable size as possible, it’s time to get to work.  With other fish in the aquarium (including the parents in many cases), the little guys face the imminent danger of being eaten.  Be prepared to remove as many of the eggs/babies as possible to either a contained area within the aquarium, or to a separate breeder or quarantine set-up. Net breeders and nurseries may be the simplest way to go in many cases, and they can be perfectly adquate for many types of fry.  Use extreme care when handling eggs and fry to prevent damage to tender cargo. Live bearing fish may be moved to the breeder net or nursery when they are close to term to trap the babies when they are born. Be careful when moving females, too, to minimize stress.

A slightly more involved and high maintenance endeavor is a second aquarium, 2-10 gallons in size that will need regular maintenance, like your parent aquarium. The set-up can be simple; sponge filter, heater and maybe a plant or some other ornamentation for cover. You can keep a few danios or minnows in the tank to cycle it and keep the chemistry stable between batches of fry. The goal is to provide them with a safe, stable environment where they can get all they need and you can watch them grow.

5-day old Nothobranchius eggersi babiesThe other important aspect is food. You want to provide your babies with plenty to eat, without overfeeding.  There are commercial fry foods available, formulated with plenty of protein and other essential nutrients for good growth and development. Some breeders prefer to create their own food. For best results, feed the fry several times a day in small amounts as opposed to once or twice in bigger quantities–tiny stomachs can only hold so much. Be sure to clean the filter cartridges or prefilters frequently to maintain good water quality.

What do I do with all of these fish?

Fry grow quickly.  It may not seem fast when you watch them every day, but in just a few short weeks your little survivors will probably be big enough to manage on their own with non-predatory fish.  By this point, you’ll need a plan for the offspring, whether you plan to sell them, trade them, or keep them. Some pairs are prolific, and they may spawn several times a year, so be sure to give some thought to where the maturing fish will be headed when they are ready. 

Baby fish in your tank can be a great surprise! It can be a lot of fun collecting babies and watching them grow up before your eyes, and it can be educational experience for you and your family. It can also be a rewarding and profitable hobby for you and fellow aquarists.  Please let us know if you have any questions about raising tropical fish fry, we’d love to hear about your experience.



5-day old Nothobranchius eggersi babiesimage referenced from wikipedia and originally posted by Denise Chan


  1. avatar

    Thanks for the interesting information. I prefer a lightly-stocked tank and my fish breed regularly. Usually all of the fry survive and thrive. I give them away, and many people want as many fish as I am willing to give them, They often ask me how many fish their tank can hold. What is the maximum stocking level for a healthy tank? Many thanks for any information you can provide.

  2. avatar

    Jan, That is one of the most basic and most difficult questions that is often asked about keeping aquariums. Unfortunately, there are no magic formulas, or trade secrets to share, every situation is unique. The old one inch of fish per gallon rule has been around since the beginning of fish keeping, and is one that I personally don’t like at all, one that is more likely to lead you down a path of trouble, that that of success. All fish are not created equal, size (and adult size), temperament and diet all play a role in how many fish you can keep in an aquarium. My advice is to do a little research about the fish you are interested in, and to take a conservative approach to stocking levels, it is not a competition to keep as many fish as possible. The other important measure for stocking an aquarium is to monitor water quality. An established aquarium, with proper filtration, should keep water quality stable, with levels of Ammonia and Nitrite at zero. If you are having trouble maintaining water quality, you may have too many fish in your aquarium.

  1. Pingback: Options on Different Aquarium Types « Can You Be Sure….

  2. Pingback: Diamond Tetra Fish - How To Breed

About marinebioblog

Read other posts by

Marinebioblog is the post name of That Fish Place - That Pet Place's aquatics and aquarium experts. Contact them through the links here or leave your comments below.