Do fish grow to the size of their aquarium?

[Summer4infinity]

I used to think that concept was BS, until my lone pregnant female guppy was in my 20L tank and had about 20 babies. A few days later she went back into my guppy tank. A week later I took 5 of the week-old babies and put them in a 4 gallon tank that just finished cycling. I noticed about three weeks later that the babies in the 4 gallon are not much bigger than they were, but the ones in the 20 gallon are 3-4 times the size and getting much more color. They have been fed pretty much the same, are in the same water parameters, etc. and they are all from the same batch of babies. Has anyone else had any experiences like this?

 

[Kittykat364]

Yes, I once had a guppy that was in a small jar and he grew to the size of the one gallon jar when we put him in it.

 

[jlk]

This is called 'stunting'. Stunting goes beyond just diet and water quality concerns but there are also hormonal issues that interplay as well. Fish excrete hormones that are inhibitory to growth. In a small tank, these hormone levels increase quickly. In the wild with zillions of gallons of water, this is not an issue unless fish become trapped in a small area of water (ie, a drought situation) and these hormones actually become beneficial to the fish's survival in tiny area. If you had changed most or all of the water of the water daily in the small tank, the babies in this tank would likely be the same size as the babies in the 20g.

 

[Ohsnapitscharity]

I'm also thinking the mass amount of micro organisms living in the older tank would have something to do with it considering baby fish eat them

 

[Summer4infinity]

The hormones and microorganisms are both great points. I learn so many new things every day with this hobby!

 

[Kittykat364]

The hormones and microorganisms are both great points. I learn so many new things every day with this hobby!

Yeah it is so interesting to have a fun hobby and learn at the same time!

 

[Summer4infinity]

I totally agree!

 

[Jmunroe]

When fish don't grow because of stunting their internal organs continue to grow causing all kinds of health issues. No fish don't grow just to the size of their tank, they simply suffer because of it until an early death.

 

[LostInFish]

In a small tank fish can grow quicker if the conditions are right. Because they don't move around as much. They grow faster. The hard part is keeping the water fresh an free of toxins. I have had fry in a large tank and a small tank and the fry in the small tank grew faster in my small tank with daily water changes. I only changed the water in the big tank weekly so that played a big part also. Water changes are a fishes best friend. Not only does it replenish the minerals needed to grow but it removes hormones that can stunt the fish. This is just my experience with growing fry.

 

[Jmunroe]

Yes water change, water change, water change. Never can change too much water. Don't think I've ever done anything less than a 50% water change on any tanks that I've had over the 25 years I've been in the hobby with a wide variety of fish. Only ever used meds a couple times because I needed to treat wild caught fish in quarantine before they went with tank raised fish. Wild fish can sometimes have nasties and not show it, that tank raised fish can't handle. I have a wild caught oscar in a 6 foot 125 gallon with 10 silver dollars(very low bio load with dollars and they eat oscar poop) and I change 60-75% of the water 2-3 times a week. Makes fish grow like crazy.

 

[Summer4infinity]

Good to know! It sounds like you guys have lots and lots of water changing experience! So changing large volumes of water won't cause a mini cycle? Right now I change 10-25% a week, depending on the nitrate test results. I'm always worried about big water changes because if I don't get the water exactly the right temp before I put it in the tanks I end of losing some of my cherry shrimp and ghost shrimp (two separate tanks).

 

[Summer4infinity]

Also, could you please point me to a good thread for water change tips... Such as good tools to use/ how to do it with less splashing/ do you use any stress products/etc... I'm still pretty new to this (6 months). I tried searching for some in these forums, but couldn't find any. I'm guessing I'm just looking in the wrong places.

 

[LostInFish]

Nice, I totally agree water changes. Gotta be the worst part about owning fish

 

[Kittykat364]

Nice, I totally agree water changes. Gotta be the worst part about owning fish

I would have a super big tank if only for the water changes!!!! (And the space, of course)

 

[Jmunroe]

Also, could you please point me to a good thread for water change tips... Such as good tools to use/ how to do it with less splashing/ do you use any stress products/etc... I'm still pretty new to this (6 months). I tried searching for some in these forums, but couldn't find any. I'm guessing I'm just looking in the wrong places.

Get yourself a python water changer or similar product and a bottle of prime. Start the siphon going and gravel vac while your tank is draining to remove all the waste from your substrate. Once your done draining the amount of water you want from your tank, add your amount of required prime to the tank( dose for the entire tank volume) and then refill the tank. I would never do less than 50% water change at least once a week and more if your stocking and tank size need it due to nitrate levels. I'm on a well and not city water so I don't have to use prime, just drain/vac and fill. You need prime or another water conditioner if your are on city water.

 

[Kongo]

It appears so. I kept a Silvershark for almost 10 years. Bought it when new to the hobby recommended by the pet shop to a 15 gallon beginner tank... It never became bigger than 10 cm, despite it was eventually moved to a 142 gallon tank I bought after a couple of years. It never looked unhealthy or became sick. Though it was of course not the optimal way it was being kept in its early years.

 

[Jmunroe]

It appears so. I kept a Silvershark for almost 10 years. Bought it when new to the hobby recommended by the pet shop to a 15 gallon beginner tank... It never became bigger than 10 cm, despite it was eventually moved to a 142 gallon tank I bought after a couple of years. It never looked unhealthy or became sick. Though it was of course not the optimal way it was being kept in its early years.

What happened to it? Where is it now?

 

[Summer4infinity]

That Python water changer looks like an amazing invention! I'm definitely going to have to get one. It is too bad there is so much misinformation about aquarium keeping. I actually worked in a pet store for a short time (20+ years ago, yikes!) and the little training we got was "wait 24 hours to put fish in a new tank, unless you add something for the chlorine, then go ahead and add fish right away. I'm still pretty new to this hobby (less than a year) and I've certainly made a lot of mistakes (I used to think cycling was just for saltwater, doh!), but have learned so much, but also still have so much left to learn! Thanks for the water changing tips! I didn't know you could put the prime into the tank before refilling it, that will make my water changes that much less complicated.

 

[Normalnot1]

Ok, this brings up a question in my mind.
With the Python, (I have one by some other name) how do you control the water temp when refilling?
I hook mine up to the kitchen faucet but only use it for refilling. Takes too much water and wastes it when you use it to vacum (drought here in AZ big time!)
I have well water and it is cold coming outta the ground, so of course I'm using some hot water too. I like to be able to do these water changes on my own, with no help but how can you do that when your tank is 20 feet away from your faucet? I mean someone has to be on the tank end and I have to be on faucet end, constantly adjusting the water temperature.
Anyone have ideas?

 

[LostInFish]

Ok, this brings up a question in my mind.
With the Python, (I have one by some other name) how do you control the water temp when refilling?
I hook mine up to the kitchen faucet but only use it for refilling. Takes too much water and wastes it when you use it to vacum (drought here in AZ big time!)
I have well water and it is cold coming outta the ground, so of course I'm using some hot water too. I like to be able to do these water changes on my own, with no help but how can you do that when your tank is 20 feet away from your faucet? I mean someone has to be on the tank end and I have to be on faucet end, constantly adjusting the water temperature.
Anyone have ideas?

Do like I do and use large 44 gal trash can to store at what ever temp u like. Mine has wheels and I use it to drain and fill all my tanks works great. Good luck!