Backyard Aquaponics
A place to discuss aquaponics

Hi all,

Dad and I have set up his system and so far lost about 100 out of 110 fish, roughly. All silver perch - I think the half-dozen catfish are still alive.

I've just read that the nitrifying bacteria are only 1/4 active at 10 degrees C, are totally inactive at 4 degrees C, and die at 0 degrees C. Does this mean that outdoor systems in winter in frost-prone regions are basically not possible (without some costly heating input)?

Or does it just mean that establishing a system in winter won't work, but you can expect an established system to still operate (perhaps at a lower stocking density) throughout the winter as long as water temperatures don't drop too far below 4 degrees?

I was thinking trout would be a better option as a winter crop, as they require cold water. But the issue of bacteria has really got me. Trout need the ammonia removed, just like any other fish.

So would you recommend waiting until warmer weather, starting again and establishing the system with silver perch, then rolling over to trout next winter, then back to perch in the following warm months etc etc?

Or should we throw some cheap goldfish in now, say 10 or so, to keep the system ticking over and then add perch as soon as it warms up in Spring?

Jimmy, i've fallen for the exact trap!

dad has about 8 of his 30 trout left.

its been something like 3 weeks now and there is no sign that there is any appreciable ammonia reduction happening.

I'd be inclined to go for your last option if and when the ast of the SP die.

Get a system cycled in the warm weather and you'll be right. I've been feeding my trout two fist fulls of feed and i have zero ammonia in contrast to dads, but my system is over a year old.

It is a harsh lesson to learn.

why not just prep your system using goldies, tuff as nuts, cheap and it means you will be in front when summer hits which means you may only have to wait two weeks instead of four. You feel like rubbish at the moment but you may as well start something so you can at least look at the pretty fish. Good luck

Here is a picture that might help you keep your eye on the prize Jimmy.

nick, thats what i thought i was suggesting with the last option

How much are you feeding your fish? If it is a new system (from experience) I know that there is a tendency for everyone to throw the fish a handful and watch the fun. (You know Joel is the worst for this!) ha ha
We had to cut our feed to half a handful each afternoon. We dont know what the water temp is anymore because the fish tried to eat the thermometer and broke it.

Very Nice vb...you won't catch me falling for that one...guts & all get weighed with my fish

So what did it taste like (no off flavours)...did you purge it 1st....and...how many in the family got to tast it

thats funny faye! Bundaberg kid had the exact problme with his trout and thermometer! LOL

I assume your question was for jimmy?

i wish i had fish that hungry! come on vb how'd it taste?

Eating it now. Bloody beautiful. Can honestly say it is probably the best tastign fish I have ever eaten - and I have eaten plenty.

I have three more in a tank purging. I didn't purge this one - and tastes like I didn't need to. I haven't fed the fish for about 4 days (because it's been so cold), so that is probably why the purging not necessary.

I think I'll suggest the goldfish option to Dad. After all, that's what I've done with my mini patio system (while I wait til we're out of the rental place and can afford the space for a full size system). Much colder weather here and the goldies are fighting fit...

my bad steve, apologies. Jimmy go with what steve said.

as an aside to this discussion, I visited a friend last week and again yesterday. Last week the eel-tailed catfish (Tandanus tandanus) in her aquarium was looking pretty sad, lying on the bottom of the tank gasping. We commented that he might not be long for this world.
Yesterday, the fish was still there, but looking better. I asked my friend and she said they had dug an old heater out and put it in the tank. When she came back to check on the fish an hour later, the catfish had moved under the heater and was looking a bit better. He has improved a lot.
Their fish tank is inside, but the water temp would have gotten down to about 12o. This is a 15cm catfish.
Warmer is better

mine are sitting at about 7C

When we put the catfish in (a week ago), they appeared to die in the plastic bag, while we were acclimatising them to the temperature. By "die", I mean all four fish simultaneously rolled onto their sides and were completely motionless, mouths open etc.

I'm sure my father was about to give himself a crash-course in swear-words at that point (given the almost 100 fish that had been lost already), when the catfish all came back to life! As we emptied the bag into the tank (having had it acclimatising for about 30 mins), the fish simultaneously "woke up" and swam vigorously to the bottom of the tank. Weird.

We've since fished out 2 dead catfish and we're not sure whether the remaining 2 are alive and hiding, or dead and hiding...