Can a Shark Grow in a Fish Tank?

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First, let’s start with the awesome part. It’s not illegal to own sharks and keep them in tanks. The problem is that sharks don’t adapt too well to captivity. Some do, but most don’t.

The white shark, for instance, cannot be domesticated. It will fall ill and die soon in captivity, no matter the living conditions at its disposal.

Since not all people have access to sharks to keep them, it’s only natural that myths have begun forming around the subject of pet sharks. One of them is the belief that sharks will never outgrow their enclosure, in this case, the tank.

This is an old myth that has withstood the test of time for no good reason. The same myth circulates with regards to goldfish who have no capped size. They can grow indefinitely until the moment of death.

With that out of the way, here are several aspects explaining why and where this myth is wrong:

  • It’s all about the food and environmental temperature – These are the primary factors that will influence an organism’s size, aside from the obvious genetic makeup. If the shark has enough food, it will keep growing; it’s as easy as that.
  • The size of the enclosure determines muscular development – Maybe this is where this myth stems from. The shark’s muscles develop based on how much physical activity the shark gets throughout the day. A too-small environment doesn’t allow the shark to move too much, hence, it will have lower muscle mass. But this has no bearing on the shark’s overall size, just his bulkiness if you will.
  • The size is determined by the skeletal frame – That’s right, the skeletal frame basically determines a creature’s size. A small but very muscular human will remain small. Just bulky and muscular. To qualify as big in size, you must have a tall and wide skeletal frame. The same goes for sharks. The size of their enclosure doesn’t inhibit the shark’s structural development at all.

Now that you know that the shark’s enclosure doesn’t determine its size, what will? What are the main factors determining a shark’s size and growth rate?

Factors Affecting Shark’s Growth

If you’ve decided to get a shark, you should know that several factors may affect its growth in captivity. Here are the ones worth mentioning:

– The Aquarium’s Size

This may seem like it contradicts what I’ve just mentioned previously, except it doesn’t. If the aquarium is too small for your shark, the creature won’t have enough room to swim and develop its musculature properly. This can cause the fish to appear smaller than its feral counterparts.

It may also be counterproductive for the shark as the lack of proper physical activity can be damaging long-term. Depending on the shark’s species, I recommend setting up an adequate habitat for the fish to roam and develop properly.

– Food and Diet

There are 2 aspects that are worth mentioning here:

  1. Ensure a diverse, omnivorous diet – Sharks don’t usually strike us as plant lovers, but it really depends on the species. Most domesticated sharks that thrive in captivity have developed an omnivorous diet, unlike their feral carnivorous counterparts. In essence, your typical tank shark will consume foods similar to those of guppies.
  2. Small portions spread throughout several meals – Your shark will benefit more from smaller meals distributed throughout the day than from one big meal. Feed your shark 2 or 3 times a day and try to give it different foods each meal. This approach will provide them with all the necessary nutrients and allow the shark to maintain its energy and positive behavior throughout the day.

These 2 approaches will boost your shark’s growth and keep it healthy, active, and happy.

– Water Quality

The water’s quality will also influence the shark’s development. Low levels of oxygen and dirty waters will inhibit the fish’s growth, which also happens in the wild. Sharks who live in oxygenated, clean, and food-abundant waters tend to grow larger and faster than the rest.

If you’re ready to get a shark, make sure that the animal will live in optimal environmental conditions. Change its water as necessary and monitor oxygen, ammonia, and nitrates levels. The goal is to ensure the ideal environmental conditions, keeping your shark safe, healthy, and growing over the years.

– Tank Mates

Sharks are competitive creatures and can become territorial and aggressive, especially towards one another. They also compete for females and food, leading to feathers being ruffled occasionally, often with more serious consequences.

This type of competitive behavior can damage the sharks as some may not get enough food. Constant aggression from other tank mates and a stressful environment may also stress out your shark, inhibiting its growth along the way.

– Genetics

This factor is clearly out of your control. If the shark’s genetic makeup limits its size, there’s nothing you can do to circumvent that. The shark will only grow within the limits of its species.

This, of course, comes with notable exceptions. See white sharks, for instance. The male can reach around 11-15 feet, while females revolve around 15-17 feet. Then you have the exceptions, with some sharks being measured at around 20 feet and weighing around 5,000 lbs.

So, no matter the species’ genetic limitations, you will occasionally encounter freaks that rewrite their species’ limitations.

How Fast Do Sharks Grow?

The answer will definitely depend on the species in question. The bamboo shark, for instance, will grow around 12 to 16 inches in its first year of life. Then, the fish will grow around 2 to 4 inches per year, pretty much throughout its lifetime.

The Epaulette, on the other hand, starts slow and picks up later. The baby shark will grow slower during its first 3 months of life, later reaching a growth rate of around 2 inches per year.

So, it all depends on the shark’s species, really.

How Big Do Sharks Grow?

This also depends on several factors, primarily the shark’s genes, diet, and environmental conditions. You have everything between the Dwarf Lanternshark, measuring around 8 inches to the Great White, reaching 20 feet in length and over 5,000 lbs.

The shark’s diet will also play a major role in determining its size. Sharks need sufficient food to maximize their growth potential. You should remember that when getting your preferred tank sharks.

Aquarium sharks will reach medium sizes, between 2 to 4 feet in length. These measurements are ideal for large tanks and outdoor ponds capable of holding larger fish. Just make sure your shark has enough room to swim and explore its habitat to remain healthy and grow fast and strong.

Sharks You Can Keep as Pets

Unfortunately, not all shark species can accommodate to life in captivity. Many will die, while others can’t reproduce and live a stressful and miserable life. There are, however, a variety of shark species that have adapted to the aquarium life, with 3 of the most notable ones being:

– Catshark

The Catshark isn’t a specimen but a group of sharks. The Catshark group forms the Scyliorhinidae family with over 160 different species under its belt. Most Catsharks will only reach around 30 inches in length, but they also have some giants among them. The largest species have specimens measuring in excess of 5 feet.

Catsharks are tropical creatures, but they have adapted to a variety of environments. It’s also worth noting that these are nocturnal animals who tend to sleep and rest during the day.

– Epaulette Shark

The Epaulette is another tropical creature that can measure between 25 to 35 inches. This fish thrives in stable environments and shows difficulties adapting to environments with fluctuating temperatures.

I suggest monitoring the tank’s temperature constantly to make sure it doesn’t exceed the acceptable upper threshold. Epaulettes fell most comfortable at temperatures around 72 to 84 °F, not much different from guppies.

Colder environments will inhibit its growth, while excessively high temperatures will weaken the animal and affect its behavior.

– Wobbegong Shark

Just like the Catshark, the Wobbegong is a class of sharks belonging to the Orectolobidae family. This family contains 12 species of carpet sharks living in mostly temperate and tropical environments throughout the world.

Most species of Wobbegong will grow up to 4 feet, although they can grow bigger.

An interesting aspect relates to the shark’s feeding pattern. The Wobbegong is a nocturnal fish, and species like Ward’s Wobbegong has a slow metabolism. They like to rest during the day and lurk around the tank occasionally during the night.

This means that the shark doesn’t need as much feeding as other shark species. Feeding them 2-3 times per week is generally enough to keep them full and happy.


You can grow sharks in your tank, so long as you accommodate them according to their needs. Each shark species comes with its unique requirements and needs regarding diets, environment, and space.

I suggest researching the topic thoroughly to decide whether you can handle a shark or not.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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