A Community and Forum For Aquaponic Gardeners

Just starting out. need help, i have questions

Hello all, I am in NorCal Monterey bay area and I want to start a 50 gal fish and 50 gal hydro plant tank aquaponics system. I want to have tilapia for fish in my system. Many questions (1) how many adult fish can i have in a 50 gal tank (2) what is the yield on the fish side of this system, how many fish will mature and how often will we be ready to eat some fish (3) I am going to have a cycling fish tank? plant tank system, so do i start the plants first to have a (filter) for the fish or should i start the fish first to build up bacteria for the plant to eat/filter or do i start them at the same time (4) will tilapia survive in this climate, winter: 60's/40's summer: 80's/50's (5) how many fingerlings should i buy to get started and where can i buy them. Thank you so much for taking the time to read this, and thank you if you respond as well, have a great day and if your in the area, maybe we could get a cup of coffee sometime. cheers.

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Replies to This Discussion

Permalink Reply by Keith Rowan on July 30, 2012 at 1:17pm

when you say "hydro plant tank" - are you talking about using a floating raft for your plants? if there is no media in the system, you need to provide filtration to remove solids - many ap systems rely on gravel growbeds as the mechanical filter - populated with worms to assist in mineralization of solids - i base bio-load on the amount of filtration - for every 100 gallons of growbed (with gravel or hydroton) you can grow out 20 to 25lbs of fish -

with a small system like you are talking about i'd only have 5 or so tilapia and i would add filtration

Permalink Reply by TCLynx on July 30, 2012 at 4:17pm

It generally takes lots more plants and plant space to support fish.

Some quick details about aquaponics

Here is a blog post about Basic Media Bed Aquaponics System Design

I would say stock less fish for a new system. 100 gallons of gravel bed might be able to support the above mentioned amount of fish if the system is mature and the operator is experienced, However, I would probably not stock a brand new system that has only 100 gallons of gravel bed with more than say 12 fish.

50 gallons of fish tank is the minimum amount of fish tank on might possibly grow edible fish in, however that 50 gallons of fish tank is not going to provide you much in the way of fish dinners very often. If your system is only going to have 50 gallons of fish tank and 50 gallons of media filled grow bed, then you should probably only start with about 6 fish.

If the plant tank is just going to be floating raft type, then you either need

A-an additional bio-filter and solids removal

B-only stock about 1 fish per 3 square feet of plant raft bed.

I'm going very simple here and giving you fish numbers rather than total weight since most new fish keepers are not in any way prepared to estimate total fish weight and figure out how many fish they need and please don't stock 20-25 lb of fingerlings into a system that can only handle 20-25 lb of fish since that system will be immediately overloaded and at risk of killing all the fish.

When starting up a new system, cycling up the bio-filter is what I think should come first (plants can happen at any time though they may not have much to eat for a while, don't stress over the plants at first.) You can do this with fish or fishlessly

Permalink Reply by Brandon Todd on July 30, 2012 at 5:25pm

Thanks for the replies, the system i was thinking would have 1 50 gal tank for fish on the ground and in front of another 50 gal tank with a medium in it for plants on cinderblocks above and behind said 50 gal fish tank. The fish tank would have a pump in it that pumps water upto the plant medium tank and then the pump turns off every 30 mins to drain back into the 50 gal fish tank.

here are the plans

http://theurbanfarmingguys.com/wp-content/uploads/2011/06/Basement-...

should i go 100 gal each?? 100 gal fish tank and 100 gal medium tank for plants? would the plants provide enough of a filter for the fish?

Permalink Reply by TCLynx on July 30, 2012 at 5:35pm

Main warning I have for such a small system is that temperature variations during extreme seasons might be a bit much for the fish if it is outdoors.

Tilapia can't handle the water temperature dropping below about 53 F depending on particular tilapia species. If the water temperature is much below 70 F they tilapia won't be eating or growing. There are fish species that can handle a wider range of temperatures but still a 50 gallon fish tank system isn't going to give you much temperature stability outdoors.

I'm in Central FL and the minimum fish tank size I like for a non temperature controlled outdoor system here is 300 gallons. If you can afford fish tank heaters for winter and can go to some extra lengths to keep things cool during extreme spells in the summer then the smaller system may be ok.

Permalink Reply by Brandon Todd on July 30, 2012 at 10:20pm

So if my climate may be a bit cold for blue tilapia then is there a fish you recomend for an outdoor aquaponics setup. Summers: 80's to 50's Winter: 60's to 40's

Permalink Reply by Keith Rowan on July 31, 2012 at 7:42am

bluegill, yellow perch, catfish - yellow perch will struggle/be stressed if the water gets into the high 80's for too long..

crappie may be another choice (i've heard that they are hard to feed train, but i haven't tried)

Permalink Reply by Brandon Todd on July 31, 2012 at 5:16pm

Thanks everyone

Permalink Reply by TCLynx on August 1, 2012 at 7:08pm

I'm very partial to Channel catfish but I like to recommend at least a 300 gallon fish tank to grow them.