Newbie - c.80-90cm wide/c.125 L tank suggestions, setup and general advice (upgrading from 19L)


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Dec 21, 2019
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I’m a newbie who was gifted a small Fluval Spec 19L tank (″ (W 52 x D 19 x H 30 cm, for reference) with 5 armano shrimp and a few fish (not sure what they are!) about 4-5 months ago.


I have some tap safe and water cleaner, and have been doing 10-15% water changes every 7-14 days. I'm in London and the water is very hard. Tank temp is c. 21'C.

I added some plants about 3 months ago (unfortunately – despite taking precautions – that brought snails too), though am having some issues with thread algae [perhaps for another thread]. But the main thing is I’d like a bigger tank – I gather easier to maintain, greater fish holding capacity, and will look better in the space. And general advice on any of the following – tank choice, set up, water maintenance & testing, stocking, etc – most welcome.

I’m fairly short on time these days (which makes me wonder why I’m even contemplating this project!), so to the extent things can be easy/low maintenance – or quickly digestible information – that’d be great!

Tank choice

Max width is 95cm (though I suspect anything over c. 90cm will be tricky to move in and out). Depth ideally up to 35cm, could go a bit deeper but ideally <45cm. Height flexible, as the shelves and be moved, but ideally 35-45cm. Anything much over 50cm will probably bit a bit domineering.

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Sorry - a bit messy at the moment...!

Whist there is a cupboard underneath which could house a filter and heater (via the 75mm hole for cables), I’d prefer to keep everything in the tank (presumably less risky re leaks; I need the cupboard space, etc).

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The obvious contenders seem to me to be the Fluval Roma 125 (W 80 x D 35 x H45 cm) or Juwel Rio 125 (81 x 31.9 x 50). The Juwel is a little higher than idea, but has the advantage of being available in white, which would blend in much better (matching the book case). Both seem to have reasonable reviews. But perhaps I should be considering something else too? Aesthetically, I prefer the squarer top design (rather than, say, the Aquael Leddy 105, which is otherwise a good size a 75 x 35 x 40).

Alternatively, something like the Diversa 112L (80 x 35 x 40), but then I’d need lights/filter/heater and to find a good/neat way of doing that.

I’d ideally go s/h if possible. The Fluval Roma 125s seem to come up often at reasonable prices (<£100), fit the space well, etc, so looks to be the front runner.


Lower priority, but I’d propose to transfer contents of the current tank - shrimp, fish, plants, rocks and gravel – once the new one was ready. I’d like to add some brighter coloured fish – including some that inhabit the higher levels of the tank. Including some larger ones too. Presumably something for a few weeks/months, once it’s all settled in. Easy to look after, get on with each over, and within capacity etc. So I'll do some research on easy community fish, but suggestions welcome.

The current gravel is a mix of Fluval Stratum volcanic soil for plant or shrimp aquarium (of which I have maybe another 2-3 kg unused) and whatever came in the tank (a finer, bluey-grey layer that sits on top).

Testing/cycling/tank transfer etc

I gather I’m probably going to need some testing kits (ammonia, nitrate and ph), possibly some nutrients (which may help keep the algae at bay). And to learn how to set it all up, cycle, water change, transfer from existing tank, etc.

This seems a good starting point:

I guess I get the new tank up and running using a bit of the gravel from the current tank (and possibly some plants?), then – once ready (perhaps 30 days?) - transfer the fish.

If there’s a good one stop guide (book?), that’d be most welcome!

Many thanks in advance.

There is plenty of good info on this site. Scroll to the bottom of the page and look for the link to "Beginner starting point". The info is useful even for non-beginners. The fish in your tank are glowlight tetras (hemigrammus erythrozonus). You can read about them here. They are best suited to soft water. They are much brighter and have a longer lifespan when they are in soft water. The link I posted is to one of the better / more reliable sites for researching info on fish species.
Many thanks Seangee - most helpful! I'll get reading!
Many thanks Seangee - most helpful! I'll get reading!
Forgot to say - up your temp to 25 degrees. Do it slowly because they are particularly sensitive to sudden temp changes. Also try to change around 75% of the water per week. 19l is really too small for them so that would help. They are also much better in big groups (I have 14) but I would not advise getting any more until they have a bigger home.
The Roma or the Rio are good choices, I guess you will just go for what is available second hand. I have a Rio 125 and am happy with the quality, appearance, filter and heater. The light is within the recommended specification but I have an algae issue, although that may not be caused by the light at all.

When you move the gravel etc over to the new tank move the existing fish and the filter media (have as much as you can In the 19 litre ready to move over) at the same time to jump start the cycle. It's a good plan to get a test kit and wait a while before adding new fish.

What is the exact number and measurement of the GH of your water? If it is hard I recommend you look at guppies, platties or dwarf rainbow fish to see if they suit your water.

I agree with Seanagee. Increase the temperature and the water changes.

BTW I'd say that plug point is overloaded LOL!

Good luck and ask any/ all questions on here - there's always someone able to help. :)
Don't be too quick to discount snails. I have MTS (malaysian trumpet snails) and a sand substrate. They don't eat the plants, don't multiply out of control (as long as you don't overfeed) and do a great job of keeping the substrate clean. You don't even see them in the daytime.

@Naughts - I never asked for the GH number because I know that you can walk on London's water :) Your fish suggestions are spot on.
Thanks all for your help and suggestions. I'm doing bigger water changes; can't get the temperature up beyond 22'C - seems to be the heaters' limit. Once everything's transferred to the new tank, I'll gradually up the temp.

It looks like I've sourced a s/h Juwel Rio 125, which I hope to pick up next week. In advance of that, I'm trying to make sure I've got everything I need to get the tank started (appreciating it'll take a while to cycle it).

I have testing strips. And a little water conditioner and tap safe (though will order more of these, given how much more I'll get through moving from 19L to 125L!).

I'm leaning towards the look of a very light coloured substrate (off white sand, perhaps? I'm leaning towards Pettex Roman White Sand 8kg), some plants (transferring existing and adding more - perhaps including some carpeting, some moss and some more grassy type ones) and some drift wood. In the longer term, more fish. Any thoughts/recommendations? Anything I've missed? (Liquid CO2? Plant fertilizer? Tank starter bacteria etc hopefully not necessary as I can move rocks and plants and filter media across to kick start things). Comparability with tankmates / substrate / plants? As above, water is very hard (London), tank mates are 9 x glowlight tetras and 5 shrimp (armano, I think).

Being a relative noob with 2 small children and a demanding job, keeping it simple / low maintenance seems sensible!

A few thoughts off the top of my head:

1) Is a light coloured substrate crazy / a rod for my own back (particularly when I already have some dark Fluval Stratum volcanic substrate)? Compatible with armano shrimp and plants? I think the lighter the better, in terms of aesthetics (going in a white tank on a white bookcase), but open to advice.

2) Moving across existing plants and rocks will inevitably mean my transferring the algae and snails already in the smaller tank. I'm not too bothered by the snails (hopefully they help with algae), which came in on the plants I bought (despite having treated them in bicarb etc). The blanket type algae which has grown off plants is less great, however! I've been removing the worst of it manually. Lights are only on for c. 8 hours at the moment. But if I'm walking into a trap, do let me know! Or if I should be regularly culling the snail population, etc...

3) Less urgently, fish wise, ideally a mix - more colourful, more contrast (size and shape) - so perhaps a few of (relatively) larger size for contrast. From above I gather guppies, platties and dwarf rainbow fish, which all look good (though all small and broadly similar silhouette), but if there's anything else (more contrasting) to throw in the mix ...

Many thanks in advance!

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Argos play sand is a good choice for a light substrate. No liquid CO2, it is actually poisonous to fish.

Ok, so I now have the Juwel 125. All very exciting. Here’s where I’m at (questions in bold – labelled by letter for easy reference):

Tank cleaned and installed.

Laid down 3kg of Tropica Aquarium Soil with (leftover from my 19L tank setup) c. 2kg of Fluval Stratum volcanic soil for planted or shrimp aquarium.

Tank was then filled with London tap water (hard!) and dechlorinated (using API Stress Coat+ - removes chlorine and chloramines).

Left for 18 hours.

Added 10kg washed sand, giving a sand depth of c. 1” on top of the soil. This optimal from an aesthetic perspective, but (A) perhaps not deep enough to prevent the soil coming up… (???) … bearing in mind the tank is likely to have amano shrimp in (I could perhaps leave them in my 19L), and (once established) I might get a few otocinclus (or other) catfish.

Added double dose of API Stress Zyme+ (contains live bacteria and supposedly helps boost the biological filter). I’m planning to do that again next week as per instructions .

Moved across rocks from the old tank and a few smaller scraps of plants, together with a dozen pond snails (cross contamination was inevitable and I figure I could always get an assassin snail or two, or some snail eating fish if I want rid of them). Added new rocks to old tank to get some bacteria going on them.

Moved across the 19L tank filter media for c. 5 hours and – before repatriating - given it a good squeeze into the new 125L

Installed 3 pieces Azelea Root, having first boiled it for maybe 4 hours, then 10 hours at 80’C, with a few water changes (which came out like tea – so much tannin!).

Added a couple of the tiny serving spoons of fish food ((B) though there’s probably sufficient ammonia coming from the soil… I assume/think…?).

Tank is now 24 hours old. Currently at 24.5’C but I’ll aim to get that up to say 27’C to help speed the cycle. (C) I’m proposing fairly limited artificial light (maybe 3-4 hours a day) during the cycle (unless you recommend otherwise)

(D) I have 6 way test strips, but these don’t test for ammonia. Do I need to buy separate ammonia test strips?

(E) Do I need to buy ammonia, or is the aquarium soil (plus snails) sufficient?

I’m planning to order some plants – probably straight vallis, java fern, java moss, water wisteria (Hygrophila Difformi) and Anubias to begin with, and then add others more slowly as it (hopefully starts to take hold). Or perhaps just get one of those plant packs where you get 50 odd samples. (F) Any comments / recommended alternative plants?
(G) I’m concerned that some of the plant suppliers say their plants are not shrimp safe (due to insecticide). Presumably soaking (I gather in bicarb solution for 24 hours) and/or leaving in the tank whilst cycling is sufficient mitigation?

(H) At the risk of opening a can of worms, there seems to be some conflicting advice on water changes during cycling…!

(I) If I keep the 19L tank going, any thoughts on what best to do with it? Breeding tank, perhaps?

(J) Any other tips/comments appreciated!

I’ll hold back thinking further about fish since it’ll be months before it’s established enough to add anything beyond the 5 amano shrimp and 9 glowlight tetras I already have (must contain my excitement!).

I'll add some photos at some point when I get the chance.

Thanks all!


Exciting times :)
A) you may lose all the sand regardless of depth as it is finer than aquatic soil.
B, E, H) @essay has great knowledge here. But you could just move all your media and livestock to the new tank for an instant cycle. Add more media for a couple of months then you have some for the small tank at a later stage.
C) sounds fine, light just needed for your plants
D) yes you need to be able to test for ammonia
F) plant choices sound fabulous
G) I don't think insecticide is easy to eradicate - consider alternative plant vendor (tropica are grown in a sterile vacuum) or
I) keeping the small tank for shrimps.
Thanks for the speedy reply Naughts!

On (A), would having a deeper sand bed help - some compaction, etc? I'd ideally like to keep the sand sitting on top, but that may not be viable (physics not on my side!).

B, E, H) An instant cycle certainly sounds appealing. I was a little nervous - being a newbie - about going for this, and because I'm going from 19L to 125L. But presumably the 19L filter bacteria is perfectly adapted to the volume of fish in that tank, and that's not changing, hence the instant cycle. I'll read up a bit more but I'd be happy to do that in principle.
Does it make a different that the new tank is not (yet) properly planted? Safer to wait (probably a couple of weeks) until it is?
Also, does it matter that the soil substrate alone may be upping the ammonia levels ("the guy in the fish shop said... [!!!]" I wouldn't need to add ammonia because the soil would provide it; though that doesn't seem to square with my [limited] understanding of a fishless cycle, where you need to know how much you're adding etc).
If I do instant cycle, once I've moved the filter media over, presumably best to shut down the small tank (or - preferable - perhaps leave it just with plants in) until the media can be carried back over in a few months' time...

G) and I) Sounds sensible! Though if I instant cycle by putting the amanos in the big tank, I can't imagine catching them to move back in a few months is going to be easy...!
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From what I've read, sand finds its way to the bottom but I've never used more than one substrate so I don't know.

I've done instant cycles a few times now and it works. I try to move some substrate as well as the filter media and I test the water daily at first. If you got your plants growing before the switch that would definitely help too. I leave my spare tank running at the moment but previously have put filter media and substrate in another (in use) tanks filter and packed it away, still really quick to set up if needed for quarantine etc.

No, you wouldn't want to move them again. My advice would be to find your plants elsewhere.
B. I know very little about these soils.

C. If there are no plants yet, leave the lights off. Once there are plants in the tank, have the lights on for as long as the types of plant need.

D. You need to be able to test for ammonia. This is the first thing to show up when something goes wrong. Ammonia is bad for fish, as is nitrite, and levels of both should not go above zero when there are fish in the tank.

E. As you are intending to plant the tank, you do not need to buy ammonia. Plants use ammonia as fertiliser and they do not turn it into nitrite. When you have the plants, put them in the tank and wait till there are signs that they are growing.

G. If you haven't ordered plants yet, look for a supplier who guarantees them to be shrimp safe. There are sellers on Ebay who state this, and the website proshrimp also sells shrimp safe plants. They may not be the cheapest but if they won't kill shrimps it's worth it.

H. Water changes depend on the type of cycling you are doing. With fishless cycling using ammonia, water changes are not needed except in a few limited circumstances. With fish-in cycling, they are necessary as any ammonia or nitrite in the water harms fish, shrimps etc. Using plants to cycle the tank, once you put fish etc in the tank you need to monitor ammonia and nitrite and do a water change of either shows above zero.
And when there are fish in the tank you also need to do a weekly water change even if the levels are both zero.

With live plants, you can do what is called a silent cycle. Plants take up ammonia faster than bacteria. If there are enough fast growing plants, you don't need to do a fishless cycle. Floating plants are often referred to as ammonia sinks because they remove a lot of ammonia. I would add water sprite to your plant list, a lot of Ebay sellers use it's latin name Ceratopteris.
Once you know the plants are actively growing, add fish a few at a time. Monitor the ammonia and nitrite levels daily to make sure the plants are using all the ammonia made by the fish. If there is no sign of ammonia, after a week or two, get the next fish.
While you are waiting for the plants to establish, monior the water for ammonia to make sure the soil is not one that leaches ammonia. If it does, you'll need to wait till it stops before getting fish.
I only ever get plants from proshrimp to be safe. Please note that fish in cycling is not an option for shrimp. They are very sensitive to ammonia so it is important that the level never goes above zero
Thanks all - most helpful.

Ammonia test kit is on the way.

Some white whispy mould growing on the wood, but I gather that's normal, not dangerous to wildlife, and goes away after a while.

Hopefully I'll get a chance to order some plants, to arrive perhaps next week. I think I'll start off lightly planted and see how I go from there - but I quite like the minimalist look, so I don't think I'll get too many.

I'm in no rush so could potentially leave the shrimp in the old tank for 2+ months to give any non-shrimp safe plants a chance to detoxify; though finding a reasonably priced shrimp safe vendor seems the better option. Or perhaps I just leave the amanos in the other tank indefinitely... !

I've also ordered 2kg biogravel and filter bags so I can pimp my Juwel filter:
. Should be able to get about 1.5kg in there, with the rest to go in the 19L tank too.

When it comes to adding fish to the Juwel (probably a couple of weeks away or more - depending on how the plants react), it seems I move over the established ceramic filter media from the 19L tank and add the fish within 24 hours. In weeks before that, the biogravel in both thanks should be getting established to help with load bearing. I'm hoping that the combination of some plants, plus the instant cycle approach (and a semi-cycle fishless cycle in that the tank will have been up and running for perhaps 3-4 weeks already) should do it. I'll of course be guided by the readings. Will keep you posted...

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