Aquaponics/ tilapia? Question for Sylvia.

Aquaponics with Tilapia seems straight forward. One question I am not sure about is the transition from full grown/harvest of the tilapia and the replacing of the mass of fish for the plants to get nutrients. What I mean is this, say you have 100 fish, adult, ready for harvest. If you take them all out and add fry, the mass of fish is way down and the plants get less nutrients. My question is, can you add fry to adult tanks and do a gradual swap till the fry get larger and you finally take out the last of the adults? For example, since the fry grow so fast, if you take out 20% of the adult fish and add l00 fry, then over the next 6 weeks or so, you take out more and more adult till they are gone. Now the fry are larger and producing enough nutrients for the plants? Bottom line, fry and adults in one tank or have a second grow up tank? Thanks Sylvia.

Richard

First off, welcome Sylvia
My question is:
In you short video, you mentioned that ratio is important, is that ratio of fish to water, or fish to plants or a ratio of all three?
Also what is the smallest system that you think is viable? What sort of space do I need available to start? My garden has very limited space.

Thanks

Welcome Sylvia, it is great to have one with your expertise here. I have been trying to convince my wife that we should start one of these systems. I have unfortunately been unsuccessful to date and any help with answers to her questions would be greatly appreciated.

Can we grow fish such as Crappie or bluegill in one of these systems?

If we can how much space would be required for each fish?

How large a tray system can be taken care of per fish tank?

What is the average cost for a basic system?

Since I am definitely not fully familiar with aquaponics, and my wife tends to want to know as much as possible before starting something neither of us have experience with, it would be wonderful if you can help us out.

I an sure she would listen to someone with your experience and perhaps I would then be able to start gathering the items needed to set up a small, starting out system.

Thank you for giving of your time and knowledge, I know everyone here appreciates it as much as I do.

Steve Lansing wrote:Aquaponics with Tilapia seems straight forward. One question I am not sure about is the transition from full grown/harvest of the tilapia and the replacing of the mass of fish for the plants to get nutrients. What I mean is this, say you have 100 fish, adult, ready for harvest. If you take them all out and add fry, the mass of fish is way down and the plants get less nutrients. My question is, can you add fry to adult tanks and do a gradual swap till the fry get larger and you finally take out the last of the adults? For example, since the fry grow so fast, if you take out 20% of the adult fish and add l00 fry, then over the next 6 weeks or so, you take out more and more adult till they are gone. Now the fry are larger and producing enough nutrients for the plants? Bottom line, fry and adults in one tank or have a second grow up tank? Thanks Sylvia.

Richard

Hi Steve. This is a great question, and one that I had myself before I got started. The reality is that the fish don't all grow at the same rate, so hopefully you won't harvest them all at the same time. You'll find that some will be "bullies" and get at the food faster, grow faster, and, as their "reward" they will be the first to reach plate size. Then there will be the "runts" that will be slow to grow because they are just getting what is left over. That said, having another tank for your next batch of fingerlings until they grow big enough to share the big kids tank (you can use the sump tank for this, if you build a design with a sump tank) is a good idea.

Rach Hasbu wrote:First off, welcome Sylvia
My question is:
In you short video, you mentioned that ratio is important, is that ratio of fish to water, or fish to plants or a ratio of all three?
Also what is the smallest system that you think is viable? What sort of space do I need available to start? My garden has very limited space.

Thanks

Hi Rach. There are many ratios that are part of a set of Rules of Thumb that help to create a well-balanced aquaponic system. The ratio of fish to water (in media-based aquaponics that is about a pound of fish to every 5 - 10 gallons of water) and the ratio of grow bed volume to fish tank volume (1:1 up to 3:1) are the most important. I go over all this in my book, online course, and our live classes in some detail.
I've seen very viable systems made out of small aquariums, but, of course, you won't be growing edible fish that way. If your goal is to grow fish for your dinner you should have at least 100 gallons of fish tank.

Bryant RedHawk wrote:Welcome Sylvia, it is great to have one with your expertise here. I have been trying to convince my wife that we should start one of these systems. I have unfortunately been unsuccessful to date and any help with answers to her questions would be greatly appreciated.

Can we grow fish such as Crappie or bluegill in one of these systems?

If we can how much space would be required for each fish?

How large a tray system can be taken care of per fish tank?

What is the average cost for a basic system?

Since I am definitely not fully familiar with aquaponics, and my wife tends to want to know as much as possible before starting something neither of us have experience with, it would be wonderful if you can help us out.

I an sure she would listen to someone with your experience and perhaps I would then be able to start gathering the items needed to set up a small, starting out system.

Thank you for giving of your time and knowledge, I know everyone here appreciates it as much as I do.

HI Bryant. Thanks for your warm welcome - much appreciated! Here are my thoughts on your questions.

Can we grow fish such as Crappie or bluegill in one of these systems? - absolutely. Just about anything that is currently being grown in freshwater aquaculture can be grown in aquaponics
If we can how much space would be required for each fish? - Figure you need about 5 - 10 gallons of water for every pound of fish for a media based aquaponic system without external solids removal. You can stock more densely if you remove the solid waste (i.e. it doesn't get filtered by the grow beds) but you then have to maintain that external filter.
How large a tray system can be taken care of per fish tank? - A good rule of thumb is about a 1:1 volume of grow bed volume to fish tank volume for a simple, flood and drain media based system, all the way to a 3:1 volume if you introduce a sump tank. I go into this in detail in my book, Aquaponic Gardening, in my online Udemy course, and in the live classes we teach at our Colorado facility.
What is the average cost for a basic system? This is very hard to answer. It depends on if you are ok with using salvaged materials, and doing most of the work yourself, or if you prefer more of a turnkey system designed and built by professionals. If you contact me at The Aquaponic Source I can help you further with a system that both you and your wife will enjoy.

Thank you so much Sylvia, I will be contacting you as soon as the current rush of emergency fixes is under control. We are having a major heat wave and were not prepared for what the 100+ heat is doing to things.