Backyard Aquaponics
A place to discuss aquaponics

Hi all
I am new to the aquaponics world,I have an ibc system up and running now for 4 weeks and have just Introduced 50 trout fingerlings each about 4-5 inches in length. My main question is how much feed do I feed them and how often,I have the lauke's barra bait as feeding pellets. Also is there any cheap diy or bought auto feeder that i can setup. Your advice would be great,thanks in advance

I use a measuring cup -feed first in the morning by measuring out a small amount and if they eat it all throw in a bit more etc etc till you find a measured amount they eat.

Then do the same again at lunch time and the same again at dusk.

If there is any left over food or not enough adjust accordingly.

Trout eat a lot and they usually hammer it all in one big flurry so its easier to measure than some other species that take their time.

Just keep in mind it is better to under feed than to overfeed.

Hi Firey

This is just to give you a starting point as to how much to feed.

Your fish are 4-5 inches long therefore their average weight will be 15grams each.

http://www.letsflyfish.com/weight.htm

you have 50 hence total weight is 50 X 15g = 750 grams.

Your water temp in South Australia is still fairly high 18 C (64 F) I'm assuming

so you would feed the fish at 3-3.9 % body weight at that temperature.

750 X 0.039 = 29.25 grams/day. As the water temp decreases your feed rate increases.

http://aquamax.purinamills.com/trout_chart.html

Theoretically, you should feed two to three times daily( ie 10grams 3X daily)

To be honest, I have only ever feed my fish once daily and they still grow.

hope this helps

cheers Lou

Thanks very much for advice,I will try and do that over the next couple of days,is it common for trout to stop feeding when put into a new tanks especially if the ph is up around 7.8 as I fed them within the first couple of hrs and they fed quite well coming to the surface but the next morning they were all sitting down deeper and didn't come to the top to feed at all. Hopefully this doesn't mean my fish are going down hill already!!!

How much filtration do you have and are you using an aerator?

How much water do you have as well? 50 trout in a single ibc system is too many me thinks.

absolutely

My system is 3 grow beds made from ibc's each with about 300mm of growing media which is the grey dolermite 20mm gravel,a sump which catches all the grow beds runoffs which contains about 300lts and the main fish tank which is a full ibc which holds 1200lts.i have based it on the same plan as Murray hallams system he made with ibc's and he said 50 fish is a good starting quantity,I hope he wasn't to far wrong.i fed fish again at lunch and noticed some coming up for feed this time. Ph is still 7.6-7.8 and nitrites and nirates levels are still low at this stage.thanks and keep advice coming,it's good to gather this extra knowledge!!

well your not overstocked in regards to filtration so your right there

I dont think too many people would suggest 50 trout in an IBC "is a good starting quantity" - except someone like Murray Hallum. If you used his origanal rule you could put in 120.

Anyways, I would suggest getting yourself a decent aerator if you havnt already and keep a good eye on em.

Your in the right place for support and assistance anyways mate

A battery backup blower or 2 would probably be a good idea with that many fish

Thanks again for advice,I have an extra circulating pump which squirts water jets down into the water and I also have a small aerator which I will upgrade to a larger one that I can run 3-4 air stones on now after talking to you guys,is the ph level likely to decrease as time goes buy now I have fish, as i tried to make it more nuetrel around 6.8-7.0 before i had the fish and it kept rising back to 7.6-7.8 thanks again

Don't stress about your PH at this stage, IT WILL eventually come down. Your water source is obviously high PH, is it tap water or tank? If you have tank water test both your tap and tank water for PH and if one is low and the other high you can do top ups with which ever is appropriate. My tank water is PH 6 and my tap water is PH 8 so depending on what my system requires I top up accordingly.

If your plants look like they are suffering from nutrient lock out from high PH then you can try adding some seasol or chelated iron, which covers most common deficiencies in plants from high PH lock out.

High ph also makes ammonia more toxic so i would suggest looking at the ammonia toxicity chart an keep a close eye on it

Yeah testing is crucial when uping feed rates to make sure your GB's/filtration can handle the extra load.
Have you fishlessly cycled this system or are you just cycling now?

Thanks for advice,I used tap water,not sure on ph,I will test tomarrow and I will also test my tank water and use it like you do if I can.i have seasol already which I was using prior to putting fish in so I can add some If needed,is it safe to add at any stage/level,ph etc.thanks again
I will check on ammonia levels,what levels are safe and yes I cycled it without fish for 4-5 weeks first,thanks