How Fast Do Blue Tangs Grow?

How Fast Do Blue Tangs Grow?

Blue tangs are one of the most common marine fish that aquarium hobbyists keep. These bright blue and black fish are beautiful, peaceful, and relatively easy to care for (as easy to care for as marine fish can be, anyway!). 

When introduced to an aquarium as a baby, it’s fun for aquarists to watch their blue tangs grow. The question is, though, how fast do they grow? What affects their growth rates? 

That’s what we’re looking at today. 

How Fast Do Blue Tangs Grow?

On average, a healthy blue tang will grow two inches every year for the first few years of their lives. After that point, their growth rate slows to one inch per year until they are full grown. 

How fast your blue tang grows will depend on a variety of external factors, most of which you have some control over. Blue tangs that are properly cared for can grow faster than this, while those who aren’t cared for properly or who are ill or unhealthy to begin with may grow more slowly. 

Factors That Affect Blue Tang Growth 


Not being fed the right kind of high-quality, species-friendly food is the number one reason why so many aquarium fish don’t grow to their full size or grow very slowly. 

Like children, fish need a healthy, protein-filled diet to grow big and strong. This is what makes it so important that fish are fed the correct food. For many fish – including blue tangs – pellets or flakes are a good staple. This diet is then supplemented with live or fresh foods. 

Blue tangs grow best when they’re fed a diet that is made up of primarily algae and algae derivatives, both of which can be achieved through pellets and commercial foods like algae wafers. Nori is a favorite among many blue tang owners. 

They can also be fed krill, bloodworms, and plankton, which are great sources of protein.

In addition to what;s being fed, frequency is a factor that plays into growth, too. For optimal growth, blue tangs should be fed small amounts multiple times a day. 

Water Conditions/Cleanliness

While blue tangs like to eat algae, they don’t do particularly well living in it.

 This being said, tank cleanliness is a crucial factor when you’re trying to help your blue tang reach its adult size. 

It’s impossible to keep a tank clean at all times, however, an effort should be made to ensure that the tank is clean enough that it won’t harm your fish at any given time. A dirty tank becomes harmful when dangerous bacteria and chemicals from your fish’s waste build up within the water column and on the surfaces within the aquarium. 

Scrub your aquarium walls on occasion, and don’t forget to siphon debris from the substrate while you’re at it. This can be done quite easily with a manual siphon. 

The condition of the water within your aquarium is a factor, too. Water changes should be done on a regular basis to ensure that the water column doesn’t become too clogged up with debris and waste. When water hasn’t been changed for a while, it can develop a buildup or harmful chemicals that come from waste and decaying fish food — these chemicals include nitrates and ammonia, both of which can cause a host of health problems. 

 During a water change, remove 25-50% of your aquarium’s water and replace it with fresh, clean water that has been adequately treated before addition. Don’t remove more than 50% unless it’s absolutely necessary, as you want to keep some of the beneficial bacteria that lives within your aquarium inside the tank. 


It should go without saying that the health of the blue tang in question will play a part in how well it grows. A fish that is bogged down by disease, illness, or an infection of some kind isn’t going to grow as well as a fish without any health complications. 

Physical injuries such as missing or nipped fins aren’t helpful, either, as they can prevent your blue tang from getting enough food to eat, which stunts their growth. Unfortunately, physical injury can lead to infections and vice versa, creating a cycle of misfortune that is hard to break. 

How To Improve Your Blue Tang’s Growth 

Give them a friend. 

Blue tangs are a somewhat social species of fish. In the wild, they can be found in pairs or small groups. On occasion, they can be found in schools as large as 12 or 13 fish. 

So, when trying to boost your tang’s growth rate, it may be a worthwhile idea to consider introducing them to another of their species. This replicates their natural environment a bit better, which can lead to stress reduction and improved growth. 

Gentle acclimation.  

If you’re tempted to skip the acclimation process, don’t! This process isn’t only important to the growth of your blue tang but also to the lifespan of it. Without adequate time to acclimate, your fish will remain stressed out while in their new home, which drains them of energy and leaves them susceptible to illness as their bodies don’t have enough strength to fight them off.

Because of this lack of energy, your blue tang isn’t going to grow at the normal rate. It may even become stunted. 

In addition, the sudden shock of being dumped into a new aquarium with different water parameters than your fish is used to can be enough to kill the fish within a matter of hours. 


Blue tangs have a pretty standard growth rate when compared with many other types of fish. They start out growing two inches a year and, by the time they are fully grown, will only be growing one inch per year. 

How quickly they reach their total length depends on a number of factors, some of which you can control and others that you can’t. To ensure that your blue tang reaches its ideal size within the average amount of time, feed it a healthy diet, stay on top of tank cleanliness, and consider giving them a friend or two to bond with. 

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