Grow outs and water changes

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
My nitrates increase by about 40% over the course of a week. The tank water is also visibly darker from driftwood tannins. Since the tank is slightly overstocked, I imagine that the mineral levels also change appreciably.

With most fish, this isn't a problem. With GBRs, I'm more inclined to pamper.


Sent from my iPhone using Aquarium Advice

The tannins are actually pretty ok, most fish appreciate them. have you tested your tap ph vs. 24 hrs later?

Sent from my SAMSUNG-SM-G900A using Aquarium Advice mobile app
 
How much do your water parameters change in a week that you would consider doing a water change every other day?

This is a good question and worthy of discussion. The idea is that you have no parameter changes. Not realistic, of course, but in a grow out tank with lots of fry you can't keep the water too clean even with daily changes. With angels, I hatched the eggs in a 2.5 gal tank. Upon hatching I started 80% daily water changes. By the time the fry were free swimming, the methylene blue was pretty much gone. I continued this after the fry started eating, but also did debris clean up on top of that.
Since Jack Wattley was mentioned, I will add an interesting tidbit from a presentation he gave up here years ago. The Miami hatchery did a 50% daily water change. They did this by dumping a 1200 gallon tank into the system and having it overflow from the tanks. What was interesting was how they determined they were changing 50%. You wouldn't be able to tell visually, so they determined the amount by measuring the pH difference before and after.
 
I'm not trying to nitpick or anything, but an increase of 40% doesn't really mean anything all on it's own. A 40% increase from 10 would be 14. I've seen many references to tanks producing 10 ppm nitrate per week. Does your tank produce more than that, that a 40% increase would put you in a "danger zone"?

I will say that I'm totally ignorant about raising fry. Just not something I've ever cared to do.
 
there are other metabolic wastes in the tank besides the 3 commonly measured for. What they are and what quantity they occur in may be difficult to determine. Suffice to say better to get it out/dilute it. Grow out tanks typically will have a lot of fish in them, relative to the size of the tank. For example 250 angels in a 30 between nickel and quarter size. At this point they are ready to head out the door.To get them to that size in a timely fashion, the water needs to be kept clean. I have had them that size in 8 weeks.
While the situation in a grow out may be different than a show tank, the principle remains the same.
 
there are other metabolic wastes in the tank besides the 3 commonly measured for. What they are and what quantity they occur in may be difficult to determine. Suffice to say better to get it out/dilute it. Grow out tanks typically will have a lot of fish in them, relative to the size of the tank. For example 250 angels in a 30 between nickel and quarter size. At this point they are ready to head out the door.To get them to that size in a timely fashion, the water needs to be kept clean. I have had them that size in 8 weeks.
While the situation in a grow out may be different than a show tank, the principle remains the same.

The limiting growth factor would be caused by the build up of the hormones released by the fish? Same with any situation really.. show tank or grow out, heavy feeding and water changing will yield faster growing specimen.

Sent from my SAMSUNG-SM-G900A using Aquarium Advice mobile app
 
The tannins are actually pretty ok, most fish appreciate them. have you tested your tap ph vs. 24 hrs later?

Yeah, my equilibrated tap water is pH 7.4. My tank pH is about 6.8. I also have a very low KH (~2.5 dKH) and, consequently, have been adding very small amounts of baking soda (~ 1/10 teaspoon) to my tank once a week to avoid a sudden pH drop.

I'm not trying to nitpick or anything, but an increase of 40% doesn't really mean anything all on it's own. A 40% increase from 10 would be 14. I've seen many references to tanks producing 10 ppm nitrate per week. Does your tank produce more than that, that a 40% increase would put you in a "danger zone"?

When doing 40% WCs, I'm usually somewhere around 12-15 ppm nitrate right before the next WC. (It's tough to tell with the API kit, but that's what I'm estimating.) I don't think that 15 ppm is necessarily dangerous for GBRs, but I'd like to keep it closer to 10.

I don't consider doing 20% WCs three days a week to be a big burden. It's basically just one preheated 5 gallon bucket. Takes about 15 min. Plus, my Horwort is hosting a ton of hair algae and this gives me the opportunity to "vacuum" it up with the siphon more often.

PNW - is the GBR tank a grow out or a show tank?

This is a confirmed pair going into a show tank. I'm not interested in raising fry but if they survive the tetras, I may try to help them along and eventually sell them to the LFS.
 
I'm glad this thread is becoming full of good info and many different scenario's. My original questioning was for a single 3 inch lyonsi in a 55 gallon. I have decided to do about 75% every other day and hoping to get an inch of growth a month.

Sent from my DROID RAZR HD using Aquarium Advice mobile app
 
What is the actual growth rate of an angelfish in the wild?

Is a rapidly growing fish an renowned indicator of good fish health? Certainly makes sense but is a rapidly growing fish natural?

Is it the constant availability of clean water that makes the fish grow faster or something else in the water rather than something that is being removed from the water?


Sent from my iPhone using Aquarium Advice
 
Is what's good for business also what's good for the fish?
Im waiting to see how your post is answered.
 
As an aside, I've read that some breeders will keep corys at temps in the 80s specifically to speed their metabolism and growth rates. It also shortens their lives.

Same for any fish really.

55 Gallon- Empty
125 Gallon- CKF and Tiger Oscar
220 Gallon- To come...
 
As an aside, I've read that some breeders will keep corys at temps in the 80s specifically to speed their metabolism and growth rates. It also shortens their lives.


There are a lot of breeder practices that shouldn't or needn't be emulated by hobbyists, IMO.
 
What is the actual growth rate of an angelfish in the wild?

Is a rapidly growing fish an renowned indicator of good fish health? Certainly makes sense but is a rapidly growing fish natural?

Is it the constant availability of clean water that makes the fish grow faster or something else in the water rather than something that is being removed from the water?

I would venture a guess that they grow faster in the wild as there is a greater supply/variety of food and a distinct survival imperative to grow as fast as possible.

Nitrate supposedly inhibits growth rate, so I imagine that maintaining as fresh of water as possible will certainly help.
All I know is it is a tried and true methodology for growing fish out fast; multiple feedings daily and daily water changes.


Is what's good for business also what's good for the fish?

that really depends on what critter you are talking about and what stage of business.

Most of the practices of LFS is not always what is good for the fish, as we all know.

But are the practices of the breeders/collectors/suppliers better for the fish or the business?

answer is again, depends on the fish and the person, but generally speaking, what is good for the fish is ultimately good for the business, if the person operating the business is smart and in it for the long haul, but not everyone plays by those rules.

Andy Sager's breeding angels project is a good example of a person that understands that balance.

these are my impressions and opinions, your mileage may vary. :cool:
 
Back
Top Bottom