Do fish age? Do fish die of old age? How to Determine age?

What is old age for you? A weak body, lost memory, terminal illness, and lots of regrets?

But when I thought my fish was aging and about to die, I really did not have many evident proofs of it, at least not the ones stated above.

The reason? Because who can tell if a fish is suffering from lost memory, hidden diseases, or old age emotional trauma? Well, not me!

Having said that, my love for fish and passion to keep them alive for as long as possible, made me dig into this whole thing that helped me know about fish’s old age and causes of death.

So, do fish age? Do fish die of old age? How to Determine age?

Yes, fish kept in a captive environment do age. But dying of old age? Yes, that happens too. This whole system of fish aging and then dying because of it is quite similar to ours. There are multiple ways of determining a fish’s old age, like skin fading, slower movements, loss of appetite, larger body, and weak stamina, etc. Hence, when your fish shows either, all, or some of these symptoms, then you can say they’re aging and to die soon.

But how can you be so sure when you’re unaware of your fish’s actual age? Because it had probably, spent some time after birth at the shop you had bought it from.

Here, I’ll tell you how I have gathered all the relevant information and put it into simpler words for everyone to understand this phenomenon.

Do fish die of old age? (Video)

Is my fish dying of old age?

This question used to pop up in my mind multiple times a day 4-5 months before my fish had died.

Although the fish was already grown up when I got it, my attachment to it was no less.

I was worried, confused, and felt helpless when I couldn’t figure out why my fish had started looking and behaving differently.

So, during my hunt for the perfect answer from first-hand veteran owners of fish, this is a brief conclusion of what I was able to gather.

  • Fish in the wild do not die of old age because they’re eaten way before that
  • Fish in an aquarium is likely to live its natural lifespan if appropriately cared for
  • Old age in pet fish is a reality
  • They have pretty much same symptoms as we do of old age
  • Their eyes pop out a little more, they get weak and don’t eat much
  • Signs like a reappearing white spot on the head also indicate old age
  • They need some extra care in last days/months like frequent water changing, warm temperature, and low water level
  • Some dietary changes also help like feeding warm food

I know the information is very brief, but I think enough to know what it’s like when a fish is aging.

But, before all this, one of the main concerns was if all these symptoms are a sign of aging or are happening because of less care and lack of quality treatment?

That is one tough call to make for a pet that you can barely touch or have any physical interaction with.

So, if it is the other way round, some of the ways to determine a fish’s age are:

  • The gap between the rings on a fish’s scale
  • Size of the otoliths (ear stones)
  • Hardening of bones

How to calculate fish’s exact age?

You can tell when a fish is aging by observing its physical appearance, routine, and movements.

But what if your fish is not that old but still showing those signs?

Then it becomes essential to calculate its actual age to analyze the cause.

See, you’ve brought your fish from some pet shop when it was already a grown-up or had already spent 5-6 months there.

So, although it’s been just a year since you brought it home, how can you tell its exact age?

Well, to be honest, there is a procedure, but certainly not for us to follow.

The reason for this is that looking into the internal organs of a fish is not possible without the usage of equipment like tweezers and micro-reader.

Plus, you need to have the scientific knowledge to get the reading that the microscope shows.

However, if you are really into it, then have a look at some of the information that I’ve tried to put together in simpler words.

  1. You take a scale from the fish’s body using a tweezer and gently put it under the microscope.
  2. The number of rings on the scale (also known as annuli) and the space between each ring help determine how old the fish is.
  3. The number of rings with wider spaces is proportional to fish’s age.
  4. Bony fish do not have scales, so their age can be determined by counting the annuli in the ear stones.
  5. You cut the bone, take out otoliths, dip it into rubbing alcohol, and then count the number of rings.

Signs that show your fish is aging

I have been a fish owner for quite a lot of time now and love them all!

And seeing those tiny species aging is a hard thing to do when you’ve cared for it like a baby.

So, it’s not really your fault all the time that they die because they’ve probably completed their total lifespan.

Here are some of the obvious signs of fish aging that I have personally experienced and also confirmed by experts.

  • Faded skin because their original colors become dull and then darker towards black and grey
  • Minimum to zero mating calls as they stop making bubble nests to attract other fish to mate
  • Laziness because they start sleeping a lot more than usual
  • Curled fins just like hair loss in humans at an old age
  • Spoiled appetite when they are no more interested in eating
  • Weak body as they find it hard to swim all the way up to breathe and come down again
  • Bigger size because they’re growing old

Now, note that these signs do not show up overnight. All of it happens gradually, and you’ll see each symptom one by one, or with a difference of days and weeks.

Signs that your fish is not dying of old age

Let’s get our facts straight, fish do not always die of old age and even if they’re showing the above-mentioned signs, then the cause may be different.

What I’m trying to say here is that lack of proper care, and attention to details like an unhealthy tank environment sometimes might lead the fish to die at an early age.

I’ve had a fair share of almost every type of experience with fish because I’ve always had a lot too many of them.

Hence, it is easy for me to explain how to tell if the fish is not actually aging but dying due to other reasons.

Have a look.

  • The water level and size of the aquarium should be enough for your fish to breath and swim in peace. If it does not match with the required conditions, then it’s possible that the fish is not dying old age or natural causes.
  • The water temperate should not be either too cold or too warm. It should be somewhere around 26-28 Celsius for the fish to maintain its appropriate body temperature.
  • The water filter should be changed every once a week because otherwise unnecessary fungus and algae will ruin the clean tank.

Do all fish age?

No. Every kind of fish has a different lifespan, so you cannot really say a fish is aging when its total life expectancy is just a year.

For example, Goldfish are supposed to live up to 15 years, Koi can live for around 40 years, Betta for 4-5 years, and Killifish live for just a year or two max.

Final thoughts

I have now become a pro at understanding fish behavior and its causes. Whenever my fish starts behaving differently than usual, then I look into possible causes, mainly aging.

But one thing that I would like to add here is that as soon as you get to know that your fish is aging and about to die, make sure to take excessive care of it, like lowering the water level and increasing temperature. Plus, you can do it by adding some warm food to its diet like smaller fish and worms.

Related Questions

What is the maximum age of fish?

According to some genuine scientific research for animals, fish can live for as long as 70 years, and it can be estimated depending on the number of annuli in the ear stones and scales.

While one of the common fish names to live maximum in an aquarium is Goldfish that can live for a maximum of 20 years.

How do you tell a fish’s age?

Fish’s age can be determined by counting the number of rings on the scales with wider spaces. For example, if there are 4 rings with a good gap in between, then the fish is 4 years of age.

The same goes for ear stones (otoliths) to count the rings on it.

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