limiting fish growth... 30 year old ( and likely false ) aquarists "old wives tales"

[Magnum Man]

it was commonly said ( before the internet ) that fish would only get as big as the tank you put them in, supposedly the fish gave off a hormone, that stunted their growth... wondering if this was propagated by fish stores??? back then... fish didn't live as long, and water changes were less prevalent... I was ahead of the curve, as we had a ton house plants, and I used fish water to water our house plants, which grew like crazy, so I inevitably was doing water changes... my fish often "out grew" my tanks back then, maybe because of those water changes, maybe because I had fish that actually lived longer than 3 months... back then is was common just to replace evaporation...

so do fish actually give off growth reducing hormones???

any other old fish keepers tales propagated prior to the www. that were very wrong???

 

[GaryE]

To a degree, pollution will limit growth. If you don't do water changes or you follow a father fish routine, some fish species will be stunted. A limiting factor on growth is death, too. Once they go belly up, they tend not to grow...

Some do release hormones that in a closed, tiny body of water like a tank will inhibit growth. Keep the water clean and they don't matter. When I was a kid, I had an over crowded 20 long full of X. variatus platys, all breeding at one inch long. That was when we were taught to do no water changes (the myth of 'old water' is making a comeback as it looks convenient). When I decided to try the new weekly water change system that was being touted at the time, the fish returned to normal size in the next generation. I thought I'd bred a new mini-variatus, but I was also 16.

Our hobby is loaded with fish lore and leftover bad ideas from the past. People were inventing new ways forward, and as people tend to do, we got lost a lot. Dogmatic minds held on to the bad ideas, others tried new and better (sometimes) things.

Here are some bad ones:
All tank or farm bred fish have no problem with any type of water;
The API test kit tells you all you need to know about your water;
Fish can't feel pain (in spite of dissection showing a well developed nervous system);
One inch per gallon works for all fish.

You'll notice every one of those ideas is convenient for the fishkeeper. That's a warning flag. It seems any time we have to choose between complex and calling for learning versus easy answers, we choose easy.

 

[Magnum Man]

I still hear mixed stories of beef heart for Discus fish... which really seems like a really odd and unnatural choice for discus, unless they hung around with piranha, in the wild... I suspect a bovine heart was hard to come by in the wild...

I suspect it was a good quality, low fat protein source, but far from a natural source of protein for the fish... I'd suspect there are better sources today...

 

[MaloK]

In my experience, It can be done with goldfish and a correctly maintained 1/2 gallon bowl can have a comet that will never look stunted but will remain around 2 inches for more than 10 years.

On the other hand It was impossible to do that with plecos that I brought full size in a 5 gallons and shown no signs of stunning too.

Guppies would start to become smaller and smaller with crowding. But still no deformations where apparent. But all lived somewhat shorter lives tho.

 

[TwoTankAmin]

I refer to much of the so called "common wisdom" in fish keeping to be Urban Aquarium Myths. I would say the despite rewriting the fishless cyling article here and especially the two on rescuing a fish in cycle gone wild, that some of these myths are being repeated, but at least less often than 12 year ago when the were many articles on failed cycles.

One of these is that one must do a big water change if ammonia is present at any level and the same for nitrite. While it is mostly true for ammonia, it is far from being a universal. But, most folks have no idea of how to determine if they should not do anything because of a low level ammonia reading. Even worse is one never needs to do a water change for nitrite unless you do not have access to salt.

The entire sw side of the hobby know their fish are almost never at risk from nitrite because they live in salt water and the needed chloride which block the nitrite from entering a fish is always present.

his is just one more example of why some keepers will never get it right. Most of us learn really early that we should not keep big fish in smal spaces. The people who think a fish only grow to the size of the tank do not keep their large growing dogs in a closet to keep them smaller. Or at least most would not.

Over the years I have spent at least $40,000 buying fish. Fortunately by their spawning in my tanks I was able to recoup those costs. Along the way I have learned a great deal about how to care for the fish I keep. With the exception of a few egregious mistakes which killed fish, my fish have pretty much lived a long time. But, I knew from day one that when I put fish into a glass box, they became my total responsibility. How long they lived, how well they did, how healthy they would be was pretty much up to me. And I very early realized that I should not keep anything for which I could not care for properly. This meant parameters, tanks size, diet and which cohabitants were OK. Plus if they got sick, I had to be the doctor to the best of my abilities.

While I am far from perfect in all of this, I can at least know that I do my best to give all of my tank buddies the best life I possibly can. All I can say it that today, going into year 25 with fish is that I still do the happy fish dance every time I see new eggs or fry in my tanks. I am not as spry as the first time I did it, but I still can do a few steps

 

[MaloK]

Another aspect that is less talked about is fish that dies young because they are too well fed and grow too fast with an excess of nutrients caused by the quality of the food used.

Some are quite potent and overdosing in vitamins and mineral have toxic effects in long term.

 

[TwoTankAmin]

I have never believed in power feeding my baby/young fish to accelerate their growth. It never made sense to me. Also, the little bit of abgelfish breeding that happend in my tanks meant feeding live food multiple times a day. This is one of several reasons I do not breed angels.

 

[MaloK]

Agree and always wondered how it could affect the whole life of the fish even if boosted like only 10% of it's life.

But I always had best results with those that prefers to eat what they find in the tank than relying only on manufactured food.

In many case it means a reliable way to introduce "Live" grown food whatever it is from, biofilm to all the possible invertebrates you can have.

But establishing such food web in a fish crowded aquarium is nearly impossible.

Of course you can take up the challenge and start looking up Refugiums. And while used mainly in Saltwater tanks.

They can be turned into freshwater protected food webs. Once established the right way, they become a real mess I would say. And they need a separate light to work.

But the messier the better it works. And It blows whatever crustacean thriving in the refugium in the tank on regular basis as live food. It's where you forcibly grow everything you don't really want to see too much on the other side.

Too much or too little nutrient, this specialized area or a tank designed to support beneficial organisms and promote natural filtration hidden from the general fauna that would snack on them until death. Will naturally compensate with what needs to be done.

The principle is simple, It Works Like Heaven...

You have to be mentally prepared to make the most outrageously disgusting filter maintenance ever possible.

But only installing a thick natural algae rail on the return of a filtration system can lasts years without maintenance and have an absolutely game changing effect on the water chemistry.