Backyard Aquaponics
A place to discuss aquaponics

I just set up my system it's a small system 35 gallon sump 55 gallon barrel tank and a 55 gallon grow bed it's a flood and drain system chop system with a split flow from the sump to the gb and ft. The water has been running for a week now and I want to start adding fish how many gold fish should i start with? And when should I start planting?

1 fish per 5 gallons if plate size. Gold fish are massive poo and pee machines. if they were large then I would start with 6 and add if comfortable with the situation. Some people plant then add fish, some the other way around. The difference is time and fish nutres. It should all just get better from fish on.

If you start with fish that are already grown, then starting from seed in the growbed can cause complications. the plants may not be able to extract nutes from the water fast enough for the fish to remain healthy. starting with fry will let the plants grow with the nute levels

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Hi. From your question, I'm not sure if you have cycled your system as yet... do some searching on this forum about what that means if needed. Unless you're prepared to lose some fish, or start with low stocking rates and feed cautiously, don't add fish until tank is cycled.

Good luck with the new adventure.

lots of people cycle with fish directly in a system (even the BYAP shop systems went down this route).
Goldfish work best since they can cope with a wider variation of system conditions than many plate/other fish.

If you regularly lose goldfish then you are doing something wrong or there is something wrong in the system.
But note the odd one still might die in first few days for other reasons particularly if they come from a pet store or a pond etc. Add the fish transport water to your system and you will get some bacteria initially.

Fish are much safer going in to a new system with 0 ammonia/nitrites than a partially or improperly cycled one.
You should run the system for about a week before adding fish - helps settle the water and also helps to find any problems and make sure aeration etc is good.


As Dave notes, it is important to have lower stocking rates during early stages - don't put lots of goldfish in initially. 55 Gallon (200 Litre) is a relatively small system. Just a couple/few depending on size of fish. 2-3 medium or 5-6 small ones. Don't over feed.

The final number of fish is actually determined by your grow beds and wet media volume (ie. filtration capacity and nutrient use) not the volume of your fish tank. Personally I would be looking around 8-10 medium goldfish in that sized system but guess you might push it higher if your grow bed supports it.


Plant straight away.
Go straight to seedlings rather than seed - you will still need some small nutrient supplementing initially.

Make sure you test you water and when adding nutrients understand the difference between seaweed extract plant food/tonics (low nitrogen/phosphorous but trace elements and potassium) and liquid fertilisers (high nitrogen and various other elements).

Dangerous Dave, The cycle thing is nice if you have all the test kits which I don't. I just fill up a bed with waste FT water and wait a week. That's my cycle. Real low tech. Yet everything is growing so far. On a very small container I recently just did, I put enough clay balls in my filter for 2 weeks to prep them. I have seedlings showing today. So that seems to assist the startup also. It is trying to grow dancing grass which is not easy I am told. A gift from a friend.

Thanks Duem. Sounds like you're making the good point that it's easy to be overanalytical about things... and that systems are often remarkably flexible/resilient. I'm definitely at risk of making the mistake of overtesting and wanting to be in control of things at too fine a level.

But having a basic understanding of the dangers of being uncycled and the things to do to avoid nitrite and ammonia spikes surely doesn't go astray. That said, it's hard to tell from the original post what level of experience/knowledge there is so maybe my advice misses the mark.

The only test I have for ammonia is my eyes and nose. If high, the water starts to turn yellow and stinks. High tech here. If low the water looks drinkable. Pull a cup of it in a clear glass and have a peek. I don't have all the bells and whistles most of you have. I still use a floss filter to pull out solids and once a week we make poo juice for the house plants. Even the wife uses it now on her plants. Any new plant or small bed starts off with a mix of 20% poo juice and 80% FT water. Take some clean FT gravel in a cup and then a cup full of FT used gravel and seed it. See which one grows better. Use FT water on the FT gravel one and plain water on the clean gravel.

On my test 1 setup. the GB has a drain at about 50 % height. I disconnected it from the air lift line 3 months ago and it is doing better now with out it. The bacteria in the holding water must have reached a good point and is feeding the plants very well so the older they get the better they seem to get. Once in a blue moon I toss a cup of FT water in it.

AP seems to be the chicken or the Egg deal. How do you cycle with out fish and how do you cycle without media? I know you can buy stuff but that is more money out the door. I like to maintain an older FT and start with that water for everything. It will need about a month if brand new.

I ended up buying six fish and throwing them in they all started out pretty nice in the tank. The next day I came out and they were all dead. I think it may have been to cold not to sure I also think it could have been the Silicon I used. It prevented mold. So I changed to a silicon made for aquariums and I'm gonna fill it up again and give it a go.

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Right now my ph is sitting pretty high in the 8.6 range is that something to be alarmed at

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From the tap it's about 8

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Silicone needs at least a 24 hour dry time to gas out. I try and give it more like 48 hours. Do you have any lime stone mixed in the FT or beds. It will raise the Ph along with other things. What was the Ph the fish came out of? A change will kill them just as fast, just a few points. Ph has to change slowly for them to survive. 8.6 is up in the death range for most fish. 7 is neutral and best for most fish

I'm gonna let it sit for 48 hrs I have pea pebbles in the grow bed.i tested it using vinegar I didn't see any bubbles

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You need to figure out what is spiking your Ph so high. If there are no buffers in the water it could change very fast. Do you have access to any other water to test out? Something with some more minerals in it.

Like from the sump or grow bed?


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