Aqua One Horizon Rimless Glass Aquarium
The Aqua One Horizon Rimless Glass Aquarium is a clean, minimalist glass tank designed for freshwater aquariums, planted tanks and aquascaping.
With no bulky top frame around the aquarium, the Horizon range gives you an uninterrupted view of the tank and works particularly well when you want the aquascape, plants and livestock to be the main focus.
Available in five sizes from 35cm through to 60cm, it's a great option for everything from compact planted displays through to larger community and aquascaping setups.
A fitted glass lid is also included, helping reduce evaporation while making the aquarium more practical for everyday fishkeeping.
Why Choose a Rimless Aquarium?
The biggest appeal of a rimless aquarium is the presentation.
Instead of a large plastic frame surrounding the top of the tank, you get a much cleaner glass-box appearance.
That makes the Horizon particularly well suited to:
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Planted aquariums
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Aquascaping
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Shrimp tanks
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Nano fish
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Small tropical community aquariums
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Minimalist aquarium setups
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Customers wanting to choose their own light and filtration
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Display tanks where appearance matters
If you're planning to upgrade to equipment such as a Chihiros light and external or hang-on filtration anyway, starting with a simple rimless tank gives you considerably more freedom than buying an all-in-one aquarium with equipment you may eventually replace.
Which Horizon Size Should I Buy?
Simply Fish stocks five sizes:
XS – 35 × 20 × 23cm
A compact option for small planted displays, shrimp and genuinely nano aquarium setups.
This size is also very popular as a hospital or quarantine tank for treating sick or injured fish. It’s easy to heat, easy to observe fish closely, and simple to keep clean. A basic sponge filter and a heater is usually all you need to complete a very effective treatment setup.
S – 40 × 23 × 25cm
Provides a little more footprint while remaining very compact.
Great for desktop-style planted aquariums, smaller aquascapes, or a slightly larger quarantine/hospital tank setup where you may need a bit more water volume for stability during treatment.
M – 45 × 26 × 27cm
A useful middle-ground size with more room for hardscape, plants and livestock while still being easy to position around the home.
Also works well as a longer-term hospital tank if you regularly treat multiple fish or want extra space for recovery.
L – 50 × 29 × 29cm
A noticeably larger footprint that gives you much more flexibility for aquascaping and small community setups.
Less commonly used as a hospital tank, but still suitable if you need extra space for larger fish under treatment.
XL – 60 × 32 × 36cm
The largest Horizon in this range.
This is our pick if you want a proper planted aquarium or small community tank rather than a tiny nano display.
The added length, width and height give you significantly more room to work with when arranging plants, wood and rock.
Bigger Is Usually Easier
If you're deciding between two sizes and have the space, we generally prefer the larger aquarium.
A slightly larger tank gives you:
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More swimming room
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More aquascaping space
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More planting room
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Greater stocking flexibility
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More stable water volume
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More room for filtration and equipment
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More options if your interest in the hobby grows
A tiny aquarium might be cheaper to buy, but that doesn't automatically make it easier to keep.
Small volumes of water can change quickly when something goes wrong.
Is Equipment Included?
The Horizon is primarily for customers who want to build their own aquarium setup rather than buy a complete all-in-one kit.
That gives you control over the equipment you choose.
Depending on your setup, you'll generally still need to consider:
For a planted Horizon setup, we particularly like pairing these tanks with Chihiros aquarium lighting because you can match the light to the length and plant requirements of the aquarium.
What Filter Should I Use?
The best filter depends on the Horizon size and what you're keeping.
For smaller models, options may include:
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Sponge filters
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Small internal filters
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Hang-on-back filters
For hospital or quarantine setups specifically, a simple sponge filter is often the best choice. It’s gentle on sick or recovering fish, provides excellent biological filtration, and is very easy to maintain.
For the larger Horizon tanks, you may also consider:
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Larger hang-on filters
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Compact canister filters
For an aquascape where you want as little equipment visible as possible, an external canister filter can produce a particularly clean presentation.
Don't choose a filter solely because it physically fits.
Also consider:
What Light Should I Use?
That depends heavily on whether you're keeping live plants.
For a simple fish-only aquarium, a basic LED may be perfectly adequate.
For a planted aquarium, we'd choose the light based on:
For easy-to-moderate planted setups, the Chihiros B Series is one of our favourite upgrades.
For more demanding high-tech aquascapes, we'd look toward stronger RGB lighting such as the Chihiros WRGB II range.
The advantage of buying a simple rimless aquarium is that you're not locked into whatever light happened to come with the tank.
Is the Glass Lid Included?
Yes.
The Horizon range includes a fitted lid.
A lid helps:
You can still remove the lid if your particular aquascaping or lighting setup calls for an open-top aquarium, but always consider whether your livestock is likely to jump.
Rimless Aquarium vs Complete Aquarium Kit
Neither is automatically better.
They suit different customers.
Choose a Horizon Rimless Tank if:
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Appearance is important
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You want to select your own equipment
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You're building an aquascape
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You already know which filter/light you want
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You don't want to pay for equipment you'll replace
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You like the clean rimless look
Choose a Complete Aquarium Kit if:
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You're brand new to the hobby
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You want the easiest possible equipment selection
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You want lighting and filtration included
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You'd rather have everything designed to work together from the start
For someone getting into aquascaping, we'd generally lean toward the Horizon-style approach.
For someone who just wants a straightforward first aquarium with everything included, a complete Aqua One or Juwel setup may be easier.
What Can I Keep in a Horizon Aquarium?
That depends heavily on which size you choose.
Potential setups include:
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Shrimp aquariums
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Planted displays
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Nano tropical fish
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Betta setups
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Small schooling fish in appropriately sized models
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Small community aquariums in the larger Horizon sizes
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Aquascapes
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Species-specific tanks
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Hospital or quarantine tanks for treating sick fish
The important thing is choosing livestock based on the adult size and behaviour of the animal, not how small it happens to be at the shop.
A fish being physically able to fit inside an aquarium does not mean the aquarium is suitable for it.
If you're unsure, tell us which Horizon size you're considering and which fish you want to keep and we'll help work out whether the setup makes sense.
Great for Planted Aquariums
This is where we think the Horizon range really shines.
The simple rectangular shape gives you freedom to build your own planted setup with:
You can then match the lighting, fertilisation and CO₂ equipment to how far you want to take the planted side of the aquarium.
A basic low-tech Horizon can be extremely simple.
Or you can turn the same glass tank into a serious high-tech aquascape.
Important Setup Tip – Make Sure the Aquarium Is Level
Before filling any aquarium:
Make sure it is sitting on a suitable, strong and level surface.
Water is heavy.
Once substrate, rock and water are added, even a relatively small aquarium becomes considerably heavier than it looks when empty.
Don't try to correct an uneven stand by filling the aquarium and hoping the glass will deal with it.
Make sure the supporting surface is appropriate before setup.
Plan Your Hardscape Before Adding Water
If you're using wood and rock, we'd recommend experimenting with the aquascape while the aquarium is still empty.
It's much easier to move rocks around twenty times when you're not elbow-deep in a full aquarium.
For planted setups:
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Position the empty aquarium
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Add substrate
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Arrange rocks and wood
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Step back and look at the layout
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Adjust it until you're happy
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Plant the aquarium
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Carefully add water
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Start filtration and heating
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Begin cycling the aquarium
Taking an extra hour at this stage can make a massive difference to how the finished aquarium looks.
Available Sizes
XS
35 × 20 × 23cm
S
40 × 23 × 25cm
M
45 × 26 × 27cm
L
50 × 29 × 29cm
XL
60 × 32 × 36cm
Design: Rimless glass aquarium
Lid: Included
Primary Use: Freshwater, planted aquariums, aquascaping, and hospital/quarantine tanks
Simply Fish Recommends
If you're getting into aquascaping or planted tanks, we think the Horizon range makes much more sense than automatically buying an aquarium kit full of equipment you may replace later.
You start with a nice clean tank and build the equipment around what you actually want to achieve.
Our main recommendation is:
Don't automatically choose the smallest one because it's cheapest.
If you've got room for the 50cm or 60cm model, the extra footprint gives you significantly more freedom with plants, livestock and hardscape.
We particularly like the XL 60 × 32 × 36cm if you're trying to build something that feels like a proper planted aquarium rather than a tiny desktop display.
Pair it with good lighting, suitable filtration and a proper planted substrate and you've got a very capable little aquascaping setup.
FAQ
Does the Aqua One Horizon include a lid?
Yes. A fitted lid is included.
Does it include a filter?
This Horizon tank range is intended as a glass aquarium that you build your own equipment around. Choose filtration appropriate for the tank size and livestock.
Does it include lighting?
Choose your lighting separately, which allows you to select a light based on whether you're building a fish-only, low-tech planted or high-tech aquascaping setup.
Is it suitable for aquascaping?
Yes. The simple rimless shape is particularly well suited to planted aquariums and aquascaping.
Can I use it as a hospital tank?
Yes. The smaller sizes are especially popular as hospital or quarantine tanks. A simple sponge filter and heater is usually all you need.
Can I keep shrimp in it?
Yes, Horizon tanks can make excellent shrimp aquariums when properly filtered, cycled and set up.
Can I keep tropical fish?
Yes, provided you choose a Horizon size suitable for the adult size, group requirements and behaviour of the fish you're keeping.
Do I need a heater?
For tropical livestock, generally yes. Select a heater appropriate for the aquarium size and required temperature.
Which Horizon size should I choose?
Choose based on the livestock and setup you want rather than simply the amount of space the empty aquarium takes up. If you're deciding between two sizes and have enough room, we'd usually lean larger.
What light works well with these tanks?
For planted tanks, Chihiros lighting is a strong option. Match the light length and output to the Horizon model and the plants you're planning to grow.
Is a rimless aquarium suitable for beginners?
Yes, but unlike a complete aquarium kit you'll need to select the filter, lighting and heater separately. That's an advantage if you want better equipment, but a complete kit can be simpler for someone who wants everything bundled together.
Can I run it without the lid?
You can create an open-top setup, but consider evaporation and whether the fish or other livestock you're keeping are capable of jumping.
