What Is The Clown Knife Fish Growth Rate? How To Foster Them

Most fishkeepers (especially experienced ones) must have been familiar with clown featherbacks (or clown-knife fishes). These tropical creatures are famous for their distinctive gray and knife-like bodies, which makes them a lively addition to any homely tank!

Raising clown featherbacks is not that challenging, but there are still certain aspects and issues you should pay closer attention to. Common questions about the clown knife fish growth rate, care tips, and more must be properly addressed before purchasing one!

Our inclusive article will lend a helping hand,  analyzing every relevant inquiry in detail. Curious as to what we are going to discuss! Keep scrolling for more! 

What Is The Clown Knife Fish Growth Rate?

Clown Knife Fish

Some reports recorded their clown featherback growing almost 20 inches in just two months, though their development slowed down after that. Another (unconfirmed) speculation is that they rise much faster in freshwaters than in other water bodies. 

Despite no specific calculations up to date (due to varied external factors like the fish’s maximum full size and the environmental water it lives in), it’s safe to conclude that this growth rate is pretty incredible compared to most similar fish types. 

In the wild, they can reach as big as 36 inches, while those kept in aquariums can only grow to 24 inches at best.

Regardless of where it lives, ensure the fishes have ample room to swim and move its body. Otherwise, its growth will become significantly hindered! 

A featherback that is well-kept and taken care of can survive 10 years or more. 

How to Speed Up The Clown Knife Fish Growth Rate

How to Speed Up The Clown Knife Fish Growth Rate

The fish’s growth will reach its optimum peak if you can guarantee its living conditions are always within safe territories. This section will detail some crucial factors you must consider when setting up the tank: 


Featherbacks are endemic to tropical regions (whether it’s Florida or Southern Asia). What does that mean? Any tank that stores clown knives must be within those appropriate temp ranges to sustain the fish’s growth and well-being.

According to most experts, fishkeepers are recommended to keep clown knives between 74 and 81 degrees Fahrenheit. Depending on the tank and your fish size, the heater should be strong enough to sustain the entire tank within those temperatures. 

Any unexpected and dramatic temp changes might lead to the fish’s unwanted stress, resulting in illnesses or even infections!

The Water pH

The water pH plays a critical role in any tank parameter. Sadly, most people overlook them. We cannot stress enough that it should be among your priorities when purchasing any fish type, not just featherbacks!

The ideal pH levels for clown knives are about 5.5 to 7. Though they do not require that much care (compared to other fishes), you must still check the water frequently, preferably at least once every week. 

Constant and careful monitoring will help you identify and fix existing issues in the water before they worsen. Otherwise, any pH level fluctuation (albeit very slight) can negatively influence how your fish develop!

Diet and Food

Diet and Food

Clown-featherbacks have a reputation for being aggressive and strong predators, meaning hunting food is one of their common hobbies. Of course, if desired, you can always train them to eat dead, live, or frozen food; nevertheless, pellets and flakes are beyond their limits.

Most seasoned fish-keepers like to feed their clown knives shrimps or live feeder fishes, keeping them well occupied before their hunting abilities develop. 

During their earlier stages, you can also give them bloodworms, earthworms, or even prawns, sliced in smaller proportions for better digestion. 

In some cases, the featherbacks can become quite picky, refusing to eat food previously eaten. If they keep ignoring one food, try another one to coax them to eat. 

Lastly, remember to remove their uneaten foods from the tank, or they will start decaying and polluting the water.

Tank Size

As we mentioned, these fishes can get pretty big (maximum 24 inches in the aquarium and even exceed 36 inches in wild water). Hence, your best bet is tanks that easily accommodate their grown-up dimensions.

A few professionals recommend a minimum capacity of 110 gallons (500 liters), but you’d better double that number on average. 200 gallons can give your pet fish more than enough space to grow and thrive in the tank!

The only problem is that few houses are spacious enough to store a 200-gallon tank. So it’s not surprising that clown featherbacks are mostly common among generous-budget fishkeepers. In certain countries, you will likely find the fish at public aquariums rather than in home tanks. 

Tank Setup

Tank Setup

Power filters are essential, creating a stronger water flow that most clown featherbacks prefer. Not to mention, they help you filter food scraps and unnecessary waste, sustaining good water quality. 

It would help if you also considered setting up some plants along the tank’s side walls and back. Such placements give the fish sufficient room to move and hide from danger. 

Other alternatives for hiding places are thick bushes and caves. Since most of them like to swim in shadowed water, we recommend putting some floating plants on the tank’s top. 

Early Disease Treatment

Ensuring all the above factors mean your fish will have a very low likelihood of catching diseases, but that doesn’t mean it cannot happen! Thus, always keep an eye on any abnormal signals on the fish’s skin, such as unusually pale color or sudden white spots. 

If the symptoms are identified early, you only need to buy some common medicine. There’s no need to go to the vet. 


Our guide has discussed the clown knife fish growth rate and how to foster your pet’s consistent and healthy development. We hope you and your fish all the best results, and feel free to write to us if you struggle in any aspect!