Breeding and Care

Learn how to take care of and breed freshwater and saltwater fish. 

Breeding aquarium fish is a fun project and fascinating display of nature in your own little micro-ecosystem. We’ll be building this section out over time with detailed guides on how to breed individual fish species.

In the meantime, here’s what you need to know (if you don’t already).

Affiliate Disclosure: Some of the links on this site may be affiliate links. This means we earn a tiny commission if you make a purchase using these links. There is no additional cost to you, and we only link to products we recommend.

1 Introduction

Bear in mind that there is a wide spectrum of difficulty when it comes to breeding fish in captivity. Some species like guppies are a breeze to breed, provided the fish are healthy and the conditions are created correctly. Others, like yellow tang, are very difficult if not impossible to breed in captivity.

This presents a set of complex ethical issues in the world of aquarium trade and fish keeping, because it means that many of those aquarium fish (the ones that can’t be bred in captivity) are wild caught. Depending on the scale of the fish taken, this can wreak havoc on natural aquatic habitats.

For this reason, and to help combat over fishing for food purposes, universities are leading the way in understanding and developing the biology of breeding tropical aquarium fish in particular in captivity. 

When you can, I recommend sticking with aquarium species that can be bred in captivity, to reduce our environmental impact on the wild places that give us these spectacular fish for our homes.

Freshwater fish in general are easier to breed than saltwater fish, and thus have a smaller environmental impact.

Packaged food is a popular and inexpensive type of fish food available in several different tastes and recipes. Below are the popular types of dried food:

2 Breeding Variety

17 day old baby Discus

17 Day old discus | Photo by © Danolsen

Not all fish breed exactly the same way. There are a few different ways fish produce offspring, and the parents’ interaction with their spawn/fry also varies.

Most of the time, the female fish will release eggs into the water column, at which point they are fertilized by the male.

2.1 Mouth Brooders

Mouth brooding just means that one of the parents carries the fertilized eggs in their mouth. There are definitely variations between species in how they use mouth brooding. This is the method of almost all African cichlids, and here’s an example of how it might go:

The male creates a nest for the eggs, entices the female using whatever that species’ method is (fin dance, etc.), and the female lays her eggs in the nest, where he fertilizes them. Afterward, here’s what happens:

  • She picks the eggs back up.
  • She carries them around in her mouth until they hatch.
  • She releases them into the water column.

There can be either maternal mouth brooding (female carries the eggs) or paternal mouth brooding (male carries the eggs), depending on the species. Some parents will eat their young once they are fry if not separated from them right away. Others are attentive parents.

2.2 Egg Layers

With egg layers, the female will either release the eggs into the water column or lay them on a suitable surface (sometimes prepared by the male) such as in a cave or among plants or substrate.

At that point, the male fertilizes the eggs, and there are varying degrees of parental participation in keeping the eggs and sometimes even the fry protected.

Again, there is variation with this among species as some parents will eat their fry – Although this is more common among males than females.

2.3 Livebearers

Fancy Guppy Photo

Fancy Guppy Photo by (c) Karel Zahradka 

The name is somewhat self-explanatory: These fish produce live young rather than eggs. In other words, the process happens internally in the female (similar to mammals) rather than externally in the aquarium.

The male fertilizes the female’s eggs similarly to mammals, the egg develops inside the female, and she releases a tiny live fish.

Livebearers tend to be an easier fish to start breeding: Because the fish is released live, it has a lower likelihood of dying in the tank because it’s bigger and more developed than its aquarium-hatched counterparts.

Examples of popular livebearers include swordtails and mollies.

3 Fish Breeding Cycle

Despite variations in how fish manage to get their little fry into the world, the general cycle of breeding is similar for all fish:


  • Eggs
  • Larvae
  • Fry
  • Young adults (e.g., juveniles)
  • Adult fish
  • Spawning (starting the process over)

4 Saltwater vs. Freshwater Breeding Behaviors

While the processes have plenty in common, there are a couple of key differences in terms of how saltwater and freshwater fish reproduce in the wild. Here are the main two:


Most commonly, freshwater fish eggs will end up in a secure, specific location, such as among plants or substrate, in a nest created by the male, or in a burrow.

Saltwater fish eggs, however, usually float freely in the current as plankton until they undergo a kind of metamorphosis that turns them into small adults.


It’s very uncommon for marine (saltwater) fish to extensively take care of their eggs and/or young in any capacity. Once the fertilized eggs are released into the current, the parents go back to their lives and the eggs/plankton are on their own.

In contrast, there are many freshwater fish species in which one or both parents actively protect and assist the eggs, and even the young fry, after the fertilization occurs.

5 Conditions for Breeding

Discus with babies

Discus with babies Photo by © Francisco? Caravana

When planning to breed, fish health is extremely important for a successful outcome. Fish that are kept in a clean and well-maintained tank will be healthier than those living in a lower water quality.

Fish that are fed a varied diet that provides them with necessary nutrients, protein, and carbohydrates will be healthier and in better shape to breed successfully.

There are two key factors to keep in mind when it comes to breeding: The first is the general health of the fish and the aquarium ecosystem, as discussed above.

The second is the conditions that are required in order for a particular species to reproduce. This is referred to in the aquarium trade as “conditioning” (as in conditioning the fish for breeding).

Here are the most common parts of conditioning a fish for breeding:



Increase temperature and lighting in the tank. In the wild, spring and rainy season is when fish usually breed. To replicate the gently increasing temperature and longer daylight hours, the temperature and lighting in the tank are both gently increased. Please note that there are specific parameters for each species of fish.

2:    DIET

Focus on providing a diet rich in proteins and nutrients, including live foods like brine shrimp. This doesn’t mean to stop feeding your fish vegetables and a varied diet as well; It just means to make sure they’re getting these nutrient-rich and protein-rich foods to help get them in top shape for breeding.

Just like the temperature, lighting, and other parameters, there’s variation between species when it comes to the best diet for conditioning. It’s important to do your own research for the specific type of fish you’re seeking to breed.

6 Final Thoughts

Hope this quick overview helps to orient beginners to the wide world of aquarium fish breeding. I definitely recommend avoiding fish that don’t breed or can’t be bred in captivity so as to minimize our environmental impact.

Saltwater fish are harder to breed, and come with significant ethical implications. You can see what PBS has to say about it here.

Fortunately, there are tons of amazing options to choose from for both freshwater species. Some of the best freshwater beginner fish to breed include mollies and guppies. Plus, guppies in particular come in a stunning array of color varieties- You’re sure to find an eye-catching fish for your tank in this family!