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psbresner
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• Posted on: 18/3/2011 12:01
How many fish in my 120L Tank? #1
I currently have 2 Rainbows (Red & Boseman), 1 Gold spotted Plec and 9 Cardinal Tetras in my 120L tank. I'm looking to get some more fish but wonder what the maximum number I could have. How do you work it out? I've tried different calculators but get different answers.

I'm fancying some Panda Corys, Dwark neon rainbows and possibly some more tetras.

Thanks

Paul
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• Posted on: 18/3/2011 12:31
Re: How many fish in my 120L Tank? #2
Hi Paul

There's no sure way to work it out unfortunately. There are various formulae you can use as a guide, but none are foolproof. The most common method has always been the "inch-per-gallon" rule, which basically says you can have one inch of fish (adult size, excluding tail fin) per one gallon of water. But it's not perfect because fish body shapes and bio-load vary so much and because, for instance, where 12 x 1 inch fish may be fine in a given tank, it probably won't suit 1 x 12 inch fish!

So, as a rough guide for you:

120 litres tank - 10% for substrate/decor = 108 litres water
108 litres is 23 gallons so you can have 23 inches of fish

Existing stock have maximum adult sizes as follows:

Gold Spotted Plec = 12"
Rainbows x 2 = 11"
Cardinal Tetra x 9 = 18"

TOTAL = 41"

So, based on that you're already overstocked and shouldn't really add any more fish
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• Posted on: 18/3/2011 12:45
Re: How many fish in my 120L Tank? #3
Just a note to follow up on that. The plec will outgrow the tank, and both Rainbows you have need to be in shoals really, plus the Red Rainbowfish likes lower temps than any of your other stock. If you're wanting to add other species it may be worth rehoming those three as they don't suit the tank in the current configuration and would give you room to add other fish.
psbresner
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• Posted on: 18/3/2011 13:11
Re: How many fish in my 120L Tank? #4

Bigger tank needed me thinks.

Thanks

Paul
psbresner
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• Posted on: 18/3/2011 15:51
Re: How many fish in my 120L Tank? #5
So if I rehome the 2 Rainbows and Plec, I'll probably sell them back to my lfs.

Then could I go for say 8 Panda Corys, 6 Dwarf Neon Rainbows and perhaps some other Tetras?

How does that sound?

Thanks

Paul
angelah
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• Posted on: 18/3/2011 15:54
Re: How many fish in my 120L Tank? #6
An alternative is to add an extra filter, an external preferably, that might help. You are on the limit anyway now, if not past it, so another filter won't hurt at all.
I suggest a JBL e 700.

Angela
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• Posted on: 18/3/2011 17:20
Re: How many fish in my 120L Tank? #7
Quote:

angelah wrote:
An alternative is to add an extra filter, an external preferably, that might help. You are on the limit anyway now, if not past it, so another filter won't hurt at all.
I suggest a JBL e 700.

Angela

Adding extra filtration, whilst generally a good idea, unfortunately does not allow us to greatly overstock. There's more to it than just filter capacity, so please don't think adding an extra filter is the answer to Paul's problem. Especially given the amount of fish he would have to add just to give the Rainbows suitable shoal sizes.

Quote:

psbresner wrote:
So if I rehome the 2 Rainbows and Plec, I'll probably sell them back to my lfs.

Then could I go for say 8 Panda Corys, 6 Dwarf Neon Rainbows and perhaps some other Tetras?

How does that sound?

That sounds like a good plan Paul, and is the right way to go about it. If you do that, add them in groups, a month or so apart to allow your filter to catch-up and minimise the risk of a "mini-cycle".
angelah
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• Posted on: 18/3/2011 17:26
Re: How many fish in my 120L Tank? #8
Please don't rap me over the knuckles quite so hard!
I didn't mean an extra filter gives anybody free scope for overstocking, but it would help in the present situation until a better arrangement could be found.
I double filter and with big filters too, but I am only 53% stocked even when the fish are fully grown.
So coming down on me like a ton of bricks wasn't necessary...!!

Angela
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• Posted on: 18/3/2011 17:32
Re: How many fish in my 120L Tank? #9
Sorry if you feel I've done that Angela, but you did say it was "an alternative" to rehoming in order to increase stock.

That maybe isn't what you meant but is how it read within the conext of the whole thread, (at least to me) and I want to make sure Paul (and anyone else reading) doesn't get the wrong end of the stick with potentially distressing results.

I certainly haven't made any reference to stocking in your own tank as it isn't something I was even aware of, purely to the matter in hand and to general rules for stock.
angelah
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• Posted on: 18/3/2011 19:25
Re: How many fish in my 120L Tank? #10
My best course is not to say anything at all, whatever it may be, because I'll be wrong.
I am sure you can all cope without my help.

Angela