# Build and care for an aquarium

**Aquariums are built inside your own stable interior.** Open the home icon's **Stable interior** menu and choose aquarium building. You place pieces in the world, using a transparent preview and your material count beside the pointer.

## Make glass, then place cubes

![Glass](/gluebook/items/glass.png) **One glass** is fired at a Kiln from **6 Scrap + 1 Sap + 2 Water**. It is a refined building material, not a new gathered resource.

A floor tile uses a **3×3 grid**. The small piece is one third of a tile in width, depth and height; it is not 0.25 of a tile. A full 1×1×1 cube contains **27 small cells**.

| Piece | Glass | Sap | Water to fill |
| --- | --- | --- | --- |
| 1/3 × 1/3 × 1/3 | 1 | 1 | 4 |
| 1 × 1 × 1 | 27 | 27 | 108 |

Select size, aim, place, repeat. The counter shows **cost and stock**, not a count of pre-crafted aquarium items. Touching faces merge into one tank and remove the inner glass. Build up to **5 full cubes high**; upper cells need support. A single cube is solid and can be jumped onto. Keep the preview valid and clear of furniture and doors.

Tap **E / Use** near a tank to inspect it. Everyone can inspect. The owner can **hold E** to move it with a transparent preview and place it again. Moving keeps its contents; unsupported placement or a join that would bypass water requirements is refused. There are limits of 432 small cells and 48 aquarium fish per account.

## Fill it before adding fish

Fill every connected cell. Each small cell holds **4 units of water capacity**. Adding glass to a filled tank also needs water for the new space. The preview quotes the cost before placement.

Fish load grows with length: **ceil(length in cm² / 100)** water capacity per fish, minimum one. For example, a 10 cm fish needs 1, a 20 cm fish 4, and a 50 cm fish 25. A bigger fish needs a larger connected tank, and every resident adds to its load. The game checks the minimum physical fit as well, so do not assume spare water alone makes a tiny box suitable.

## Care is a recurring material cost

Use the tank's **care** action to refresh it. A full tank uses **25% of its water capacity** per change, rounded up. Missing water is added to that bill. Occupied tanks also consume straw and sap as feed ingredients: straw is ceil(total fish load / 20), sap is ceil(load / 40), each at least one.

Care is due every **2 days**. A tank needs fresh water before adding a live fish. Living fish neglected beyond their **7-day deadline** die and retain a **poor condition / neglect** record. Fresh water does not revive them. The deadline persists through logout and updates; moving fish around is not a way to reset it.

For a display that needs no living-fish care, use a [trophy cube](/gluebook/gluniverse-fish). It is a different item and stacks four high instead of five.

*Reviewed 2026-09-27. Market prices and remaining world stock are live, not fixed by this guide.*