Review: 10366 Tropical Aquarium from LEGO® Icons

Following our interview with the designers, today we'll be looking at upcoming LEGO® Icons set 10366 Tropical Aquarium, which will be released this week. The set has attracted as much attention for both its recolours and its price, so I was keen to take a closer look.

Products in this article were gifted by The LEGO Group; the author's opinions are their own.
This article contains affiliate links to LEGO.com; we may get a small commission if you purchase.

10366 Tropical Aquarium

• Release date: 13 November 2025 for LEGO® Insiders, 16 November for all
• Pieces: 4154

Price: 

• US$ 479.99 on LEGO.com US
• CA$ 599.99 on LEGO.com Canada
• GB£ 399.99 on LEGO.com UK
• AU$ 699.99 on LEGO.com Australia
• NZ$ 799.99 on LEGO.com New Zealand
• DE€ 449,99 on LEGO.com Deutschland
• NL€ 449,99 on LEGO.com Nederland
• FR€ 449,99 on LEGO.com France

Other countries click here

5009823 Fish Tank Filter & Fish Food

• Release date: 13 November 2025 for LEGO® Insiders, 16 November for all. Ends 19 November 2025 / while stocks last.
• Pieces: 177

A gift with purchases of 10366 Tropical Aquarium, for early buyers. 

"Expand the amazing aquarium with this Fish Tank Filter and Fish Food set. The filter sits outside the main tank with its intake tube and water spill positioned inside. You’ll also spot a stray fish who has wandered inside the filter. A box of fish food decorated with a hungry LEGO fish completes the scene."

View on LEGO.com

New mold: Fin 1 x 4 with Bar Handle (7511)

The set introduces a new fin element and you can read more about the design of this new mould in our interview with LEGO Element Designer Matéo Dupureur. 

The fin appears in several colors throughout the model:

• 5x Reddish Orange (6576899)
• 5x Bright Light Yellow (6576893)
• 8x Trans-Green (6576888)
• 8x Light Aqua (6553189)
• 3x Trans-Clear (6576891)

The design appears rather alien, with a 3.18mm bar acting as the only connection point to the rest of the LEGO® System. However, the relationship becomes more apparent when you examine the curves.

When the edge opposite the bar is vertically aligned, the inner curvature of the piece matches the profile of the 3 x 1 curved slope family (e.g. 50950). In this position, the fin measures just shy of four modules long, and two modules (five plates) tall.

Attached to clips, multiple fins can be positioned to form a fan shape with negligible gaps between them. In the context of the set, this technique is used to create the tails of the various fish included.

Brought to its natural conclusion, it takes about 20 fins to form a full circle. There is some slight room for variation, due to the mismatch between the longer and shorter curves.

Tablescraps

Examining the element, I was reminded of the petals of a flower, which inspired this tablescrap of a water lotus. I would not be surprised if we saw this fin appear in future sets in the LEGO® Botanicals line.

In transparent colors, the fin is reminiscent of flowing liquid. Coupled with a round plate 1x1 with underside clip (5264), I used it for the stream of water in this statue of a spitting fish.

Recolours

The set features a significant number of recolored elements; 21 in total. These elements span the LEGO colour palette, to create the colorful underwater environment of the set.

• 2x Plant, Bush 2 x 2 x 4 in Lavender (6576887 | 6064)
• 29x Hat, Chef / Baker in Dark Purple (6577021 | 3898, 4307)
• 48x Equipment Broom End in Light Aqua (6576889 | 90826)
• 12x Equipment Broom End in Trans-Clear (6576898 | 90826)
• 19x Light Cover with Internal Bar / Bionicle Barraki Eye with Hole in Bar in  Opal Trans-Dark Pink (6576906 | 4278)
• 19x Animal Body Part / Plant, Tail  Middle Section with Pin Holes in  Opal Trans-Dark Pink  (6577024 | 5717)
• 8x Plant, Leaf 2 x 6 x 1 with 2 Studs in  Opal Trans-Dark Pink (6552657 | 3565)
• 19x Light Cover with Internal Bar / Bionicle Barraki Eye with Hole in Bar in Medium Lavender (6576905 | 4278)
• 19x Animal Body Part / Plant, Tail  Middle Section with Pin Holes  in Medium Lavender (6576901 | 5717)

• 9x Brick Round 1 x 1 D. Tube with 45° Elbow and Axle Holes (Crossholes) at Each End in Reddish Orange (6576894 | 7324)
• 16x Animal / Plant, Coral / Sea Weed in Reddish Orange (6576890 | 49577)
• 16x Ghost Effect with Bar in Bright Light Yellow (6576896 | 5500)
• 25x Equipment Mop Head in Sand Green (6576904 | 24085, 76750)
• 33x Plant, with Bar and Off-shoot with Stud in Light Nougat (6576895 | 1566)

• 2x Technic Panel Bell, Half Curve 10 x 11 x 5 1/2 in Dark Orange (6576897 | 7345)
• 1x Slope Curved 4 x 5 x 1 2/3 in Nougat (6576886 | 85834, 4898)
• 2x Plate Special 1 x 2 with Angled Handles on Side in Medium Nougat (6576900 | 92692)
• 10x Creature Body Part, Barb/ Claw with Clip in Medium Nougat  (6576902 | 16770, 30936)
• 5x Pneumatic T-Piece (T Bar) in Medium Nougat (6577022 | 4697)
• 16x Plate Special 2 x 2 with Bar Frame Round in Tan (6576903 | 7068)
• 24x Brick Arch 1 x 3 x 1 2/3 Curved Top in Reddish Brown (6576892 | 5843)

Rare elements

The set also contains a considerable number of rare elements, which appear in three sets or fewer.

Appearing in a single other set, we have the following:

• 2x Plate Round 1 x 1 Swirled Top / Poo in Light Bluish Gray (6546846 | 3441)
• 3x Wedge Sloped 45° 2 x 4 Triple in Dark Tan (6487880 | 47759)
• 8x Plant, Leaf 2 x 6 x 1 with 2 Studs in Trans-Clear (6548957 | 3565)
• 1x Slope Curved 1 x 6 in Tan (6544405 | 6801)
• 1x Brick Round 6 x 6 with 4 Side Pin Holes and Center Hole in Tan (6525731 | 18897)
• 3x Brick Special 1 x 1 Studs on 4 Sides in Bright Pink (6542265 | 4733)
• 2x Brick Round 1 x 1 D. Tube with 45° Elbow and Axle Holes (Crossholes) at Each End in Dark Tan (6559757 | 7324)
• 2x Brick Round 1 x 1 with 3 Bars in Black (6507603 | 6331)
• 6x Technic Brick 1 x 3 [3 Pin Holes] in Black (6572774 | 5565)
• 4x Brick Curved 1 x 2 x 1 with Curved Top in Reddish Brown (6573746 | 5841)
• 20x Plant, Fern 3 x 4 x 2 in Dark Red (6529631 | 5151)
• 4x Brick Round Corner, Curved 2 x 2 x 2/3 Quarter Circle in Dark Red (6544515 | 5852)
• 6x Brick Round Corner, Curved 2 x 2 x 2/3 Quarter Circle in Bright Light Orange (6549868 | 5852)
• 4x Brick Round Corner, Curved 2 x 2 x 2/3 Quarter Circle in Lavender (6552225 | 5852)
• 6x Brick Curved 1 x 2 x 1 with Curved Top in Trans-Orange (6549670 | 7191)
• 1x Slope 45° 2 x 1 Inverted with 2/3 Cutout in Yellow (6534029 | 2310)
• 17x Brick Round 1 x 1 Open Stud in Yellowish Green (6546464 | 3062)
• 29x Hat / Pith Helmet in Yellowish Green (6468079 | 30172)
• 4x Brick Arch 1 x 3 x 1 2/3 Curved Top in Dark Bluish Gray (6540220 | 5843)
• 12x Technic Pin Connector Round [Slotted] in Olive Green (6470069 | 29219)
• 9x Technic Pin Connector Round 1L [Beam] in Reddish Orange (6483789 | 18654)

The following elements appear in only two other sets:

• 15x Tile 3 x 3 Curved, Macaroni in Tan (6547395 | 79393)
• 1x Slope 45° 2 x 4 with 2/3 Inverted Cutout and no Studs in Bright Light Orange (6536557 | 5540)
• 4x Plate 4 x 4 Corner in Dark Red (6544175 | 2639)
• 2x Technic Brick 5 x 5 Right Angle (1 x 4 - 1 x 4) in  Dark Bluish Gray (6477164 | 28973)
• 1x Slope Curved 4 x 1 No Studs in Medium Lavender (6529614 | 11153)
• 2x Technic Beam 1 x 2 with Towball Straight in Light Bluish Gray (6506199 | 5995)
• 1x Technic Beam 1 x 2 with Axle on Side in Orange (6540720 | 7244)
• 4x Technic Pin Connector Hub with 1 Pin with Friction Ridges in Green (6515234 | 65487)
• 2x Plate Round 1 x 1 Swirled Top / Poo in Medium Nougat (6554053 |  3441)
• 11x Technic Axle Connector Smooth [with x Hole + Orientation] in Dark Green (6529196 | 59443)
• 9x Technic Pin Connector Round [Slotted] in Reddish Orange (6474012 | 29219)
• 33x Brick Round 1 x 1 Open Stud in Light Nougat (6546466 | 3062)
• 24x Headwear Accessory Crown Long with Bar in Orange (6527031 | 25516)
• 89x Tile Special 2 x 2 with 2 Quarter Round Cutouts in Medium Azure (6542401 | 3396)
• 18x Brick Round 1 x 1 diameter Tube with 90 Degree Elbow (2 x 2 x 1) and Axle Holes (Crossholes) at each end in Reddish Orange (6529503 | 25214)
• 1x Slope Curved 2 x 2 with Stud Notch Left in Dark Red (6545155 | 5095)
• 1x Slope Curved 2 x 2 with Stud Notch Right in Dark Red (6544518 | 5093)
• 1x Plant, Banana in Flame Bright Light Orange (6512533 | 33085)

Finally, there are the elements which appear in three additional sets:

• 2x Dome 1 x 1 x 2/3 in Trans-Black (6552219 | 6908)
• 4x Tile Round 1 x 1 Quarter in Reddish Orange (6492073 | 25269)
• 6x Slope Curved 1 x 4 with Stud Notch Right in Dark Red (6558855 | 5414)
• 6x Slope Curved 1 x 4 with Stud Notch Left in Dark Red (6558914 | 5415)
• 4x Slope 45° 2 x 1 with 2/3 Cutout [New Version] in Medium Azure (6188112 | 15672)
• 1x Slope Curved 2 x 2 with Stud Notch Right in Yellow (6506376 | 5093)
• 2x Brick Round Corner, Curved 2 x 2 x 2/3 Quarter Circle in Dark Azure (6527162 | 5852)
• 2x Wheel Arch, Mudguard 2 x 3 x 1 1/3 with 2 x 2 Plate in Dark Pink (6518735 | 49097)
• 36x Plant, Leaf 2 x 6 x 1 with 2 Studs in Trans-Green (6544173 | 3565)
• 2x Technic Axle and Pin Connector Angled #3 - 157.5° in  Dark Tan (6485347 | 42128)
• 1x Technic Beam 1 x 9 Thick in Dark Blue (6434420 | 64289)

Building experience

The model is constructed using a whopping 41 bags of parts. The first seven of these are used to construct the base of the aquarium.

A cave with a sea crab is constructed next, followed by a treasure chest. The crab is mounted to a sliding plate, which allows it to go in and out of the cave when a LEGO® Technic axle is rotated.

To position the treasure chest at an angle, a base is constructed using a combination of Mixel joints in a fixed position, and 2L bar with towball (22484, 67692) inserted into hollow studs. This allows two of the towballs to be positioned outside of the LEGO System grid, while still remaining firmly in place.

Bags 15 through 21 are devoted to the assembly of the azure backdrop of the aquarium. A variety of curved tiles are used to add some slight texture to the studded surface. Bubbles, shells, and snails also decorate the backdrop.

Two sea kelp growths are anchored to the backdrop, helping to break it up a bit. A mix of trans-green and dark green leaves do a very effective job of refracting light to give the illusion of flowing seaweed.

With the base and backdrop built, construction shifts to the coral that inhabits the tropical aquarium. The first to be assembled is a bubble-tip anemone. The tentacles are attached to meshing Technic gears, allowing them to all move at once when a handle is rotated. Some branch coral is mounted behind the anemone which, ironically, is not the color Vibrant Coral, but Light Nougat.

Another anemone is constructed next, using a recoloured Technic 10 x 11. x 5.5 curved half bell (7345) that originally appeared in 21357 Disney Pixar Luxo Jr. (read Elspeth's review of set 21357 Luxo Jr.) as a housing for the anemone.

To angle the tentacles, a 1L bar with clip (3484) is attached to the underside of an assembly of LEGO Technic bricks and connectors. This assembly is subsequently connected to an elevated 6L bar (63965, 28921) so that it rests in an angled position.

A rocky shelf is constructed next, featuring two orange coral colonies along the top, possibly intended to represent sun coral. A number of crowns with bar (25516) are arranged to effectively represent the individual coral polyps, nested inside a crown of LEGO coral (49577).

Next, a pair of yellow and purple coral growths are built, which attach to the previously-constructed rockwork. To create the yellow coral, several ghost effect pieces (5500; see Tom's analysis of part 5500) are angled to envelop one another, creating a very organic structure. The purple coral is constructed from a large number of recoloured chefs' hats (3898, 4307).

Even more interesting usage of minifigure headwear follows, with pith helmets (30172) used to create the corallites of a coral seemingly inspired by the Favia genus. A coral is created using recoloured mop heads in sand green (24085, 76750).

This final coral specimen uses broom ends (90826) to achieve its shape and finely-lined texture. These are connected to several 2x2 plates with round bar frame (7068), which remain relatively rare in sets.

Additional plants are added to the aquarium next, helping to fill some of the negative space in the fishtanks. While I could not determine whether these plants have real-life counterparts, they seem quite at home in the simulated underwater environment.

Throughout the building process, a variety of fish are constructed to inhabit the aquarium. These include two varieties of angelfish (upper-left and lower-right); a rainbowfish (lower-left); and a striped brickfish (upper-right) which is a fictitious fish species developed for the set. 

Completed model

The aquarium is an impressive model for display, full of clever parts usage and unusual recoloured elements to satisfy builders. At multiple points throughout the construction process I found myself quite impressed by the building techniques the model designers managed to utilize.

Regrettably, the set also feels like a lesson that bigger isn't always better. The decision to devote a significant number of bricks in the set to building the tank, base, and backdrop detracts from the overall building experience. This is illustrated in the fact that the first fish and coral (arguably the highlight of the set) aren't constructed until the builder is nearly two-thirds of the way through the 500-page construction booklet.

Personally, I would have much preferred to see an approach modeled on the LEGO® Botanicals line, with multiple sets each centered on one or two different varieties of fish, coral, or underwater plants that builders could combine to design their own aquarium.

In conclusion, the set is well-designed and looks great on display, but suffers from a building process that feels artificially extended – which becomes a considerable issue for a set of this size and, at US$479.99/ £399.99/ €449.99/ AU$699.99, a considerable price.

READ MORE: The designers of 10356 Star Trek U.S.S. Enterprise NCC-1701-D™ introduce the upcoming set

Help New Elementary keep publishing articles like this. Become a Patron!

A huge thank you to all our patrons for your support, especially our 'Vibrant Coral' tier: London AFOLs, Antonio Serra, Beyond the Brick, Huw Millington, Dave Schefcik, David and Breda Fennell, Gerald Lasser, Baixo LMmodels, Sue Ann Barber and Trevor Clark, Markus Rollbühler, Elspeth De Montes, Megan Lum, Andy Price, Chuck Hagenbuch, Jf, Wayne R. Tyler, Daniel Church, Lukas Kurth (StoneWars), Timo Luehnen, Chris Wight, Jonathan Breidert, Brick Owl, BrickCats, Erin and Dale, Thunderdave, Jake Forbes and our newest top-tier patron, H.Y. Leung! You folks are better than inverted cheese slopes.

All text and images are ©2025 New Elementary unless otherwise attributed.