The spawning habits of aquarium fish are fascinating. When it comes to reproducing, fish fall into one of these five spawning types.
Fish are one of the most versatile breeders in the animal kingdom. Through all of the different species of fish, several different spawning methods are used. It is truly amazing to see how fish have adapted to suit their individual water conditions to pass out their genes!
Mouth brooding is an egg incubating practice that is used by several different types of fish. It can be broken down further into paternal or maternal mouth brooders – whether the female or the male is the one who carries the eggs. Mouth brooding is exactly what it sounds like. The fish spawn, the eggs are released by the female, fertilized by the male, and then one or the other will pick them up and carry them in a special pouch in their chin area called a buccal cavity. The eggs will stay in the parent’s mouth until they hatch, and are developed enough to be released into the world.
Some examples of paternal mouth brooding are wild type bettas and tilapia. Paternal mouth brooding is not as common as maternal mouth brooding. Maternal mouth brooders include fish such as African cichlids. Even rarer, some fish use bi-paternal mouth brooding, where both of the parents take some of the eggs.
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Fish who bubble nest typically live in low oxygen, low flow, calm, and even shallow waters with higher levels of humidity. They build a clump of bubbles by taking in air and blowing it out. The fish will spawn, place the eggs into the next, and then tend to the next until the fry hatch. Often times it is the male who guards the nest, but on occasion the female will also chase away intruders.
The most well-known bubble nesters are bettas. Other bubble nesters include gourami, and even the electric eel.
Egg scatterers release and fertilize their eggs externally. The female drops her eggs, the male fertilizes them, and they are carried off in the current. There is no parental protection for these eggs whatsoever, because they often are laid in fast moving waters. Wild fish that use this spawning technique often live in fast moving rivers and streams. To increase the survival rate hundreds of eggs are dropped at once and many males release milt to fertilize them. Because they are not protected, many are lost to predators and environmental factors, thus the large amount of eggs. Aquarium fish who are egg scatterers are koi, tetras, danios, goldfish, and barbs.
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Egg layers do just that. Sticky eggs are laid on a surface and the male swims by and fertilizes them. The parents will often guard these eggs from predators. Common fish that lay eggs are angelfish, dwarf cichlids, rainbowfish, and killifish.
Live bearers are some of the most common fish kept in the aquarium because of the ease of breeding. Males fertilize through internal means, like mammals. The female the carries the fry, and when the time comes, she releases, or drops, live fry. Common members of this spawning type are guppies, mollies, platys, swordtails, and some half beak species. They usually do not have as many young as an egg layer would because the fry grow and develop inside.
As you can see, fish are versatile in their spawning and fry raising practices. Because of the drastic differences in water ways, from puddles to ponds, rivers, streams, and even the aquarium, fish have evolved and adapted to ensure that their fry have the best chance of survival possible.
Summer Davis is the mom of three kids, four dogs, and several tanks of fish. She boasts a passion for all animals, whether they are in the water or on land. This fish aficionado has kept many different species in her time, but holds a special place in her heart for wild and domestic bettas. When she’s not talking about fish, Summer “spins” her extra time as the director of a baton twirling organization.