How Big do Brook Trout Get?

Brook trout are known for being of smaller sizes, but that’s not the whole truth. In actual fact, the largest brook trout on record is 31.5 inches long and weighed 14.8 pounds.

The average weight of a brook trout is 2-6 lbs, and the average length of a brook trout is 6-12 inches.

Growth Rate of a Brook Trout

The main reason why people think of brook trout as small trout is that they don’t grow as fast as most other trout.

As we mentioned above, the average weight of a brook trout is 2-6 lbs, which is small compared to a rainbow trout, whose average weight is 2-16 lbs.

One reason why brook trout may be smaller than other trout is that they are slower to mature.

Normally a brook trout will mature after two years; although some brook trout can spawn after one year, it is not typical.

Compare this to rainbow trout who mature between 1-2 years. This gives rainbows at least a couple of months’ head start on brook trout.

Stocked brook trout grow at a faster rate than wild brook trout during the winter; however, during the summer, studies show there is not a huge difference between the growth rate of stocked brook trout and wild brook trout.

On average wild brook trout grow between 8-20 cm per year, and increase their weight 50-300 grams per year depending on food sources.

Stocked brook trout grow between 6-18 cm each year with a weight increase between 60-500 grams.

What is Considered a Trophy Brook Trout

How Big do Brook Trout Get?

Trophy brooks are hard to come by. Given that the average size of a brook only gets to 12 inches, you would want a bit more than that to be considered a trophy.

Most people would consider a 15-inch brook trout a trophy. 

If we were to look in terms of weight, there are plenty of 3lb brooks on record as trophy fish, but most of these fish are caught on a very light line. 

So it would really depend on the tackle; if you use a line as light as 2lb, a trophy brook would be anything over 7lb 8oz, which is the current record.

If you’re using a 16lb line, you would have to pull up a 10lb 12oz brook to match the current world record.

What is the Largest Brook Trout Ever Caught

The largest brook trout ever caught was 31.5 inches long and weighed 14.8 pounds. John William Cook caught the trout on the Nipigon River Ontario on 21 July 1915.

There have been stories circulating of another potential world record trout that was caught in Manitoba.

The trout was said to be caught in Barbe Lake during a fishing competition by Tim Matheson. However, Matheson being only a catch and release angler did not want to kill the fish, so he measured it, took a picture, and released it back into the water.

To qualify for the world record with the IGFA, Matheson would have had to kill the fish. So today, the record from 1915 still stands.

The 1915 world record was also likely a much heavier fish when first caught. Dr. Cook was on a seven-day fishing trip when he caught the fish. 

Dr. Cook and others who were there that day claimed the fish was around 20lbs. However, due to having no means to preserve the fish for the duration of the trip, the fish started to deteriorate.


A lot of controversy surrounds the records of brook trout; perhaps that is because there aren’t so many large brook trout found in the wild.

Stocked brook trout tend to grow a lot heavier than wild brook trout but not much longer. They also don’t seem to grow faster during the summer months.

The average brook trout is around 4lbs and 10 inches. Brook trout can get as big as 32 inches long and 20lbs

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