Here's something that got me thinking?

If I wanted to know the age of a tree I would cut in down and count the rings. But how can you work out the age of a fish? And for that matter, how long do they live normally? My questions are for Brown and Rainbow trout? I took a rainbow just under 2lb yesterday and to me it just didn't look as healthy as others I have come across. Got me thinking? Didn't put up much of a struggle for a fish that size and I wondered whether it was just an old timer that couldn't resist. It seemed leaner than usual with more reddish colour than normal pinkish rainbows. Can you help? Or am I way off the mark?

How do older fish taste in comparison to younger ones?

At this point I will qualify my question by telling you I am a novice!

Thanks

If you have a scale from the fish, you can read age rings on it in exactly the same way as on a cross-section of tree. It's a long time since I did this, but as I recall, there are narrow and wide bands corresponding to summer/winter growth, exactly similar to timber.

Rainbow trout live for 4-5 years.Brown trout can live for 15yrs. a 2 lb rainbow from a fish farm will be 2-2.5 yrs old.
You can age fish by the rings on their scales under a microscope.
Old fish.tase pretty bad.
Rainbow trout don't grow old enough to taste bad.

Jim

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The Fishermans Friend is the Flirty Fly,Fickle Food for Fleeting Fish.

Fish scales have rings like on a tree, only on fish one ring does not equal one year. In summer when the fish grow quickly the rings are wide apart and in winter they are close together, so in simple terms you look for light and dark groupings on the scale. 1 light group plus 1 dark group equals one year. Because farmed trout grow at a more even pace these scale patterns are all but impossible to determine. Trout have quite small scales so are not easy to read.
If you kill a fish for the table try removing the operculum which is the bony plate covering the gills. Dunk it in very hot water to loosen the skin and then rub the plate clean. You'll be left with a nice semi-clear plate and if you hold it up to strong light the growth patterns are much easier to read. Only works on dead fish though.

Some species are much easier to read than others. Chub are normally a doddle as they have lovely big scales; grayling are very clear and can be read easily as well. Similar with roach and dace. Pike, barbel and perch are dreadful.

You'll need to watch for replacement scales. This is where a fish has lost some scales and has re-grown them. The centre of the scale up to the point at which the new scale has grown looks like crazy paving and is useless for ageing.

Thanks for the interesting info about age of the fish. I can confirm that I decided not to invest in a microscope, but BBQ'd the culprit this after! I can safely say that it was not an 'old timer' as initially suspected as it tasted v.good with a drizzle of fresh lemon.

Probably a proper "cock" stockie which has survived the accepted triploidisation process!
if it had large milt sacks when gutted you would know for sure,
regards
bert

That surprises me.

I would have expected a 2lb rainbow to be around 1 year old. I am sure it will depend on water conditions (purity and temperature) and diet.

Does get me wondering, how old a 15lb rainbow is, it must have massively faster growth than other fish, otherwise it would need to be 6 or 7 years old.