Backyard Aquaponics
A place to discuss aquaponics

Ah, Haven't looked at a mape of Australia lately and didn't remember where Perth is. Does it really stay warm enough there to keep tilapia without having to heat your tanks? Water temps getting below 10 C would probably do most types of tilapia in. I know that Blue tilapia, which are some of the more cool hardy tilapia, don't usually recover from water temps below 12 C and they really don't grow much at all till the water temps get up above 21 C.

I have a 300 watt heater arriving soon, I am hoping it is powerful enough to keep the water temperatures up although I am worried and suspect I will need another, although time will tell, would someone in Perth or similar climate know what power is required?

They want to be good fish a 300 watt heater will cost about $1.50 a day to run

It takes a LOT of heat to keep a fish tank even a few degrees above ambient temps, so a greenhouse will be really helpful to cut your power use. You could also keep fish indoors in winter and bring them out when temperatures moderate. I doubt the 300W would do the trick without protection...

Then again, I don't know local conditions......

Ev, Tilapia are fast growers if temps are right and I think it is worth while to have a couple small indoor breeder tanks to have fingerling size fish to move outdoors when temps get right. Can raise Tilapia outdoors in the warm 6 months and trout in the cooler 6 months. Both of which grow really well. A little more work and investment but two crops of fish and 4 crops of veggies! Layer meat ducks and chooks, I'm comin to your place for supper!

I'm probably going to differ a bit on this one. Tilapia can be fast growers if the water is really warm (talking 30 C) and you have all male stock and are feeding them really high quality high protein feed for their first few months.

To be more realistic, if you are breeding your own, you will likely have mixed gender, females don't grow nearly so fast and hardly at all while they are not eating due to breeding and breeding activities also slow the growth of males. I've dealt with this to some extent by keeping my tilapia in a cage within a bigger tank, this just means they can't pick the eggs back up and so the female will keep eating though I'm sure some energy is still lost to breeding activities but they are quite crowded in there so at least no one is getting beat up.

Anyway, I've hand my tilapia for a year and a half and none are outrageously huge though all the original stock are of eating size though that is quite variable.

If you don't mind cleaning small fish to eat, then you probably could grow tilapia out in 6 months if you heat the water a bit at the start but it could be a lot of extra effort for only minimal benefit. Might be far easier to get advanced silvers that can survive winters.

Well... So I've read they are fast growers, being I haven't done it myself outside an Aquarium I have to defer to those who have, Although I do hope to have better results than 18 months. Where I'm at I have to have a qualified Greenhouse to move them out the house and I hope to have that assembled by spring. Good luck with what ever you decide.

Hi Ev,

Can I ask do you also feed the fish pellets?

Over winter rarely do I feed them they can nibble some pond algae, warming up now so yes I feed them pellets daily.

Thanks to all the helpful suggestions above it looks of it my work is not complete after all and I will hold back on new fish a little longer

1: Will look at closing in the greenhouse,

2: Greenhouse type cover over filter bed, although I still want my Motorbike frogs easy access, any ideas please.

3: Adding a solar heat collector, once again any idea please, am thinking I have an unused 1x1m 15 cm high unused container(former small black filter bed) which I could put a perspex cover on and run water through during the day

Ev,

I tried something very similar,

but found that algae grew thick and fast and condensation blocked some sunlight. Perhaps a loose layer of black pond liner that the water could run beneath would keep the algae from growing while heating the water well.

Alternatively, I also found that my tilapia were far less hungry in winter, required lots less food, and produced lots less waste, so I needed far less growbed. I partially covered some growbeds with glass I had laying about and placed a reflective back on the north side (south for you!) to add sunlight, and made the growbed into a partial solar collector as well as increasing dim winter sunlight for plants in the bits of growbed not covered by glass. With all this I could keep the water temps no more than 5degC (10degF) above average outdoor temps.

A greenhouse doesn't need to be perfectly sealed unless you are in a really cold climate. You are just trying to keep a little warmer for the cool months. I like the glassed over grow bed idea. Could probably have the tilapia system separated out from the other system and glass the growbed for it for the winter and if all else for it is insulated it might be effective. And throwing some sort of insulating blanket over the tank and grow bed for the really cold nights would help too.

What pump are you using in the duck pond that doesn't jam up on a regular basis?

Great post, keep us up to date! I am contemplating doing exactly this... so I would like to know about potential pitfalls before I have to deal with them or spend more money to fix them.

mmm pump to use that doesn't jam up?, maybe really no such thing.

My system has a large filter section of cut up pvc pipe cylinders and a green filter tray.

I clean out the sediment from the duckpond about once every year although it could last much longer.

The green filter bed needs attention every month in summer less in winter as it grows and restricts water flow out of its drains, a mild flaw in my system IMO.