Backyard Aquaponics
A place to discuss aquaponics

I have Tilapia. Ten of them, to be exact, in the fish tank of my system.

Well, two of them decided to break the rules and give us over 100 fry to raise as well. I was able to give about about half of them, recently.

Today marks their first month. So, they are still a bit small yet. But, how long should I wait, before introducing them into the system fish tank, with the other, larger Tilapia? I have about 20 more than I need. So, I can afford to have some eaten, if that is the case. Not something I really WANT to have done. But, in case I make a mistake and can't get them out in time.

woo hoo!! good job on the breeding!

x2 on this question as i am on this same boat and was also wondering. my larger fish are 5 to 7 inches long and my fry (not from my larger fish) are 1/2" to 2"

It was a shocker to us, for sure. Somehow, either the fry, or while they were still unhatched, were siphoned from the fish tank via the SLO, and taken for one heck of a roller coaster / log flume ride over to the RFF.

I figure they hatched in the RFF, on the morning, just before we checked the strainer.

Well, they saved me from having to set up a breeding tank, at least.

I would be over the moon with some surprise eggs. What size are your parent tilapias? There was lot of difference in the size of my tilapia, 2 inch to 7 inch and ive decided to separate them. The smallers ones seem to be happier without the bigger fish, but they did wel anyway. make sure the size of the feed fits all :p

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I have ten of my original Tilapia in the fish tank (1,000 liter IBC tote). I would say the largest are probably about the same - about 7" (18 cm). The fry are not 2" long yet. I am sure, best case, the big Tilapia would chase them all over the fish tank. I would probably have to put something inside to give them a place to hide in, if I were to put them all together.

I have a couple of the original ten that are slow growers, and have been since I first got them in June. They, fairly quickly, out grew my 70 liters aquarium. I transferred them on July 10th, to the fish tank.

These little guys, between 60 and 70 of them, are doing the same now. So, I am going to have to do something with them soon. Or, I will be buying another aquarium - something I really do not wish to do at this time.

I guess in an aquaculture situation with multiple tanks you would be grading fish by size.
May be that you have to look at the extra tub/tote as an option.

you could use a screen to separate fish (fish net or something) but that would restrict the room for the larger fish.
but the issue is the larger fish need the space more.

i am curious to see what you have decided to do. i read your posts again and its crazy! we have the same quantitiy and size of fish! hehe. i had 11 larger tilapia, i went out to check on the system a few days ago and found half of one floating. he was a victim of cannablism! now i have 10. and i ordered 50 fry a while back and they sent me extra. i have 60 to 70 and they are roughly 1" to 2". I had these little guys in a small 10 gallon aquarium up until yesterday. i made them a 25 gallon home... nothing fancy, more temporary than anything else.

Are your fry eating like mad? Geez, every time we pass the aquarium, they act as though we are starving them!

Anyway, as of this morning, I haven't done anything. Yesterday evening, however, I was looking at a 208 liters (55 gallon) blue drum I have outside. I was using it for the solids I pump from the RFF / Swirl Filter. But, for the moment, I am going to just let them go down the drain. I'm more concerned with other things - like the fish.

I haven't put them into the fish tank, for fear of the same thing you experienced - and knowing they are omnivores. I would hate to see these little guys become meals for the larger Tilapia, especially after how lucky they were to make it this far. (They were born, or at least as eggs in the fish tank, then were sucked through the SLO into the RFF / Swirl Filter where they hatched.)

Anyway, I was considering trying to do something along the lines that you did. My problem, simply put, is lack of space. I am limited to 12 square meters here, total, for my system. (Property adjacent to the apartment I rent.) I don't have the space for much else where my system is set up. So, I will have to think about my options, prior to adding another tank to the system. I do, however, wish I could just set something up like you have. That would solve my problem until they were large enough to look after themselves in the large fish tank (IBC tote).

I was considering having a 188 liters (~50 gallon) tank built, using 10mm (~ 3/8") glass. The guy wants $120 USD to build it, though. Just not sure if I want to put that kind of money into an aquarium, just for fry to grow out a bit. But, if I did go that route, I could use my 60 liters (~15 gallon) aquarium as a filter / sump for it.

Fantastic idea you have, though, for sure. I'm glad to see you were able to sort it.

redeemED, aside from having the liners in and a germinating shelf above the sump, this is what my system still basically looks like.

HAHA!! yeah! Exactly what mine do! Whenever i came into the room they would go CRAZY! If i even went NEAR their tank they would rush to the top anticipating the food. I had them in a small 10 gallon aquarium and whenever i was around it seemed as though they would watch me! they definitely knew who i was! haha it is crazy! If someone else they didnt know went near them they would run away to the far corner and "hide." Now that they are in their new home, they act as if they dont know me. Either that or they are still mad at me for netting them! lol. 1 problem i found with my new home for them, a bunch have ended up in the Swirl filter. I counted 20. It was totally my fault though! i didnt use my usual method of a cap with a bunch of holes drilled in it at the bottom of the SLO. So i have 20 little turds in the swirl filter... I am just going to leave them in there for now.



WHOA! thats crazy money! you cant find a used aquarium? or even build one yourself? I have 2-55 gallon aquariums that i wanted to use in my system. 1 for breeding tilapia tank, and one for the fry to grow out. Then, all extra males that are large enough would go into a separate grow out tank. Well, the point is that i tried drilling 55 gallon aquarium #1 (a hole in the side for SLO) and BAM! glass shattered when the drill was halfway through the glass! 1 week later drilling aquarium #2 and SUCCESS! my first ever hole drilled in glass! so i was brave enough to drill a second hole and again success! i had 2 holes drilled into 55 gal aquarium #2 and was happy as can be! i went to install the piping for the SLO and BAM! cracked the glass! too much pressure on the glass ( i hit the 90 fitting to make sure it was in all the way) totally sucked! So now i am going to attempt to repair these tanks. I have never done anything like this but i think i can manage because of this youtube video:
https://www.youtube.com/watch?v=pG7C9GQRuA4

You might even be able to build a small aquarium with used glass windows/doors.
https://www.youtube.com/watch?v=HSKIT2OLOYQ

Now, I want to tell you that you have a beautiful setup! I am working with less space than you on my current system as it is at my brother in law's house. I will eventually start building at my home when i am confident. I have drawings in my thread of my design.

That's how all of our fry were originally found, in the RFF / Swirl Filter. I'm sure yours will be fine in there for a while. May want to toss some food in for them, though. We had like 9 that were hold outs, after we had the majority of others in the aquarium for a couple of weeks. The ones in the aquarium had grown considerably larger than those left in the solids filter. Considerably larger.

No doubt. I almost had a stroke when he gave me that price. I will see if I can find a local glass shop here in town. Finding used things are pretty difficult, especially specialized items like a 50 gallons sized tank. Smaller tanks? Probably could find them.

Thanks. It's temporary. We have 2 hectares (~5 acres) of land at my g/f's farm, where we can do just about anything we want. Trouble is, I have to build a suitable living space for us there, before moving.

EDIT: Oh, drilling glass is not something I would look forward to doing, especially on a large aquarium.

I finally did it, Ed.

As I previously stated, I was looking at the blue drum (55 gallons / 208 liters) as a possible tank. Just wasn't sure how I would go about it. However, after seeing your post, I was pushed over the edge to go that route. Thanks for that, by the way.

I didn't have room anywhere to pipe their new digs into the AP system, so we decided to keep them in the house, until we can transfer them to the IBC tote.

Here is what I did:

Tank / SLO Water Line
1 - 55 gallons (208 liters) recyclable blue barrel, cut at the 35 gallon mark.
1 - length of 1 inch (25 mm) PVC pipe (length will vary)
2 - 1 inch (25 mm) T couplings
1 - 1 inch (25 mm) 90° elbow
1 - 1 inch (25 mm) ball valve
2 - 1 inch (25 mm) end caps
1 - 1 inch (25 mm) Uniseal

Fill & Return Water Lines
1 - length of 1/2 inch (13mm) PVC pipe (length will vary)
1 - 1/2 inch (13mm) 45° elbow
2 - 1/2 inch (13mm) 90° elbows
1 - 1/2 inch (13mm) T coupling
1 - 1/2 inch (13mm) ball valve

Filter & Pump
1 - 5 gallons (19 liters) bucket
1 - submersible water pump
1 - mechanical filter media material
1 - biological filter media material

very nice! what did you do for the bottom of the SLO to not suck up fish?

We added a "T" coupling on the bottom of the SLO. I then ran 2 - 8" PVC pipe nipples, along with end caps, into the "T". On the lower 180° of each nipple, Tha (my trusted employee) drilled suction holes all the way down each one.
It looks similar to these, except longer and without the holes drilled in the end caps:


It keeps the tank clean, so far anyway.

make sure you test any aquarium glass before you attempt to drill it. A lot of tanks (55 gallon tanks especially) are made with tempered glass. You cannot drill tempered glass, as you saw even if you manage to get the hole in the glass they will shatter when they have a load put on them. My understanding is that all 55 gallon aquariums (and larger) are usually tempered glass. On smaller tanks a lot of times the bottom is tempered but the sides are not. If you know the tank is not tempered then drilling glass is pretty easy with a diamond bit hole saw. I tape both inside and outside of the glass where I want my hole, the tape helps to hold the drill bit from walking to get the hole started (or you could clamp on a piece of wood with the proper size hole in it for the bit to keep it from walking), then just slow and steady and have a glass of water on hand that you can keep dripping on the glass to keep it from getting too hot.

You can test to see if the glass is tempered by wearing a pair of polarized sunglasses hold a known piece of tempered glass (laptop monitor, smart phone screen) on the other side of the glass. If you see a rainbow through the glass then your aquarium glass is tempered.

For those of us here in the U.S. I would recommend finding your nearest PetCO pet store. Several times a year they have their $1 a gallon sale that you can buy most common size aquariums from 10 gallons to 55 gallons for $1 a gallon plus tax. I just picked up a 55 gallon for $60 to use in my greenhouse as a 'tweener' tank. I will use it for quarantining new fish but also use it for different stages of raising fry. I ordered 10 blue tilapia that I'll be placing in my 240 gallon aquarium in my house, once they have fry I will have a few different grow out tanks indoors (probably consisting of 5 gal, 10 gal, 20 gal, 40 gal) then I will also have the 55 gal out in the greenhouse that I can move them in to in the spring if I'm not quite ready to take my winter fish out yet (I plan to run trout in the winter and tilapia in the spring, going to pick up my trout this afternoon!)