What fish in Melbourne?

[wey2go]

Pondering on the idea of starting Aquaponics system in my parents' backyard. Keeping them occupied as well as growing their own food.

What is a good fish to keep in Melbourne?

Is it too cold for fish like the Silver Perch? My backyard swimming pool is typically around 10 - 12 degrees Celcius in winter.

By the way, I have introduced some rainbow trout into my unused salt water swimming pool. Fish seems to be happy but water does not look very good (green pea soup).

Thinking of running the water through UV Clarifier. Hope this will clear up the algae.

[GaryD]

Hi Wey2Go,

Once they learn how, your parents will find growing their own fish and vegetables satisfying.

Silver Perch would be my choice. Of the natives, they are probably the most tolerant of lower temperatures.

I'd suggest that you start fingerlings in a smaller tank at the beginning of each winter.....one where you can keep the water at around the 22 -25 degree mark. The idea is that you grow them as quickly as you can in the optimum temperatures so that they are well advanced by the time that the warmer weather comes around.

You then move them to the larger tank to finish growing them out.

Rainbow trout prefer very clean water.....remember they are usually found in pristine mountain streams. Your trout will cope very well with colder weather but will find the summer an ordeal.

The pea soup conditions affect most aquaculture systems at some stage or the other until they reach a point of balance.

A UV filter will help to clear the water but it will (over time) lead to a boron and manganese deficiency in your plants. I periodically use one to clear the water in my outside tank.

Give me some more information about the size of your system. How big are your tanks/swimming pools? How many fish do you have and what size are they? What growing systems do you use? If you don't have plant growing systems, what are you doing to facilitate nitrification?

Keep asking questions.

Gary

[wey2go]

Hi Gary,

Growing own fish and vegetables is not foreign to my parents. They are from Malaysia and have always live in rural area. Until recently, dad still keep catfish in a few tanks. It is the changed in weather and conditions, that they have to deal with. Also, topping up the tanks with rain is easy over there. So, they never had filter etc. Just use a bucket and get some water from the fish tank for the plants and next rain will top up the tanks again.

On my own backyard, my swimming pool is estimated to be around 30,000 litres. Currently, I only have 12 rainbow trouts in there. Not too many to start with as I was not sure they will live in ex-salt-water swimming pool water.

I have introduced some plants and water lily into the pool. Water is still cold (typically 11 degrees) and I think they are still mostly dormant.

Have ordered a fish pond biological filter. That is to come in about 1 week. For the moment, I am running the swimming pool pump (1.38kW !!) for 15 mins every 2 hours and filter the water through the swimming pool filter and back to the pool via a spa attached to the pool. With the spa, the inlet generate lots of air-bubbles through its Venturi (I think this is correct). This also aerate the water. Not the best but the trout seems to be happpy to have the water circulating.

Replacement water pump is a more decent 185Watts with around 18,000LPH capacity.

Need to find what is the best vegetables that will tolerate slightly salty water until the pool water get diluted out over the next few seasons.

Yes, lots of questions to ask. Hope to meet more Aquaponics practitioner in Melbourne.

[GaryD]

Hi Wey2Go,

The conditions that your parents experienced in Malaysia permit aquaculture in its most simple form.......no need for biological filtration.

Rainbow trout will not only live in saline water but they will actually thrive in it. Rainbow trout grown in saltwater are marketed as Ocean Trout.

See http://www.australian-aquacultureportal.com/industrygroups/mix_finfish_sal_trout.html

The cold water will not bother the rainbow trout either.


Have ordered a fish pond biological filter.

My only concern about a fish pond biological filter is that it is designed to keep a pond biologically stable rather than supporting the sort of fish weights that will be encountered in an aquaculture system.

If you keep fish weights on the light side, you will be able to maintain a relatively simple system.

Brisbane scientist Vivienne Hallman operated an even simpler aquaculture system than your own. See http://www.cityfarmer.org/fishfarm.html


Need to find what is the best vegetables that will tolerate slightly salty water until the pool water get diluted out over the next few seasons.


Take a look at http://www.abc.net.au/gardening/stories/s696236.htm for more information on vegetables which will tolerate high salinity.

Gary

[josh]

On reading this thread it would appear that the general advice is to go with Silver Perch. I am south of Brisbane near Stanthorpe which can get pretty cold in winter so I imagine that Silver Perch would be good?

[GaryD]

Hi Josh,

Silver perch would be the best choice for Stanthorpe. For them to prosper, they will need to be kept within the optimum temperature range of 22 - 28 degrees C.

My view is that we should rear fingerlings in tightly controlled conditions during winter so that they are as large as possible by the time that the summer comes around.....with a view to having them at harvest weight by the time the next winter comes around.

Gary

[Rob]

Hello
I am also in melbourne and still looking into fish appropriate for melbourne weather , like you say weather is to cold at 10-12 degrees and sometimes in single digit temperature perch cant be sustained ? you think what about running a heater. kind reagrds Rob

[Murray]

Rob, Melb is a bit cold in winter. The two fish suitable for there are Murray Cod and Silver Perch. If you do not provide some heat in winter then the fish will not feed and therefore not produce any waste to grow your veggies. It just depends on how keen you are to keep things going.
I have had to heat my tanks this winter even here in Brisbane for my Silver Perch. Without heat the temp would have slid down to 12 deg. They would survive, but only just. They are more likely to get disease etc.

There was some discussion about solar water heaters on the forum a while back. I am going that way next winter with some electric heating for the overcast wet periods.

[fishfood]

Hello
I am also in melbourne and still looking into fish appropriate for melbourne weather , like you say weather is to cold at 10-12 degrees and sometimes in single digit temperature perch cant be sustained ? you think what about running a heater. kind reagrds Rob

hi rob i am in sunbury and run silvers and rainbow trout i go through sydnem all the time pm me if you would like a chat

[twintragics]

I am in Geelong with 400 baby silvers 60mm in a shed enclosed 5000lt aqualined gal tank. At 12C they will nibble once per day, at 14-15C they will have one good feed per day, at 17C they will chew their heads off morning and night. If i had a 30000lt pool, i would buy trout fingerlings at easter and grow them out b4 chrissy. They need plenty of air, you must stop feeding at 20C and they will start dying at 23-24C. However they do grow very quickly at 16-18C.

[fishfood]

I am in Geelong with 400 baby silvers 60mm in a shed enclosed 5000lt aqualined gal tank. At 12C they will nibble once per day, at 14-15C they will have one good feed per day, at 17C they will chew their heads off morning and night. If i had a 30000lt pool, i would buy trout fingerlings at easter and grow them out b4 chrissy. They need plenty of air, you must stop feeding at 20C and they will start dying at 23-24C. However they do grow very quickly at 16-18C.

yep my trout are nearly plate size now water temp still 17

[GaryD]

Hi TT,

I'll be keen to see how your Silver Perch go over time.

In Queensland, the experience seems to be that Silver Perch won't grow much past 350 grams in well-stocked recirculating aquaculture systems which is why SP growers up here use ponds.

Has anyone grown Silver Perch out past 350 grams.....and, if so, what was the stocking rate?

Gary

[twintragics]

yes, they will put on a kilo in a pond environment in 12 months Gary, really seems to suit them. I got them for their hardiness. Got babies (overwintered in a pond, sturdy lil ******s,) so as they grow, my system can handle the gradual increase in bioload.

[wey2go]

Some update. My rainbow trouts (10 of them) are still alive and growing in my "pond" (swimming pool). Not sure about their weight but largest is probably around 40 - 45 cm now. Probably time to buy a fishing rod to fish them out. :)

Recently added some Silvers (about 120 of them) into the "spa" side of the pool. Erected a simple netting at the spillway into the pool to keep them there but some silvers escaped into the pool side where the rainbow trouts are! A school of the silvers (20 or so) are now living at the shallow part of the pool now. They are in company with 10 gold fishes which I put into the pool to rid of mozzie larvae. Found 3 dead silvers so far after being sucked into the filter by the pump.

The silvers absolutely love crushed water snails.

Pool water is now clearing. Back 3 months ago, it was green pea soup. The pool water is brownish tea colour. On a clear sunny day, can see the bottom of the pool which is about 2m deep.

Lots of aeration going on with a 16,000LPH and a 11,000LPH pump going all the time. And a little 6,000LPH experimental pump (15 mins on 45 mins off) feeding a plastic pot filled with gravel and with 2 tomato plants growing. Just testing if the plants will survive the salty water (pool was an old salt-water swimming pool).