30 Gallon Fish Tank: Stocking and Layout for a Planted Setup
Updated October 2026
A 30 gallon fish tank is the smallest common size with a 36 inch front pane, and the version to buy for a planted layout is the 30 breeder. Its 18 inch depth front to back gives your hardscape room to step back in layers. The standard 30 shares the length on a 12 inch footprint, so it plants like a taller 20 long.
Work out which 30 you own first, then stock to the footprint rather than to the number on the box.
Standard 30 or 30 breeder: the footprint decides the layout
The two glass versions share a 36 inch length and little else. All figures below are manufacturer figures from the Aqueon Weights and Measures sheet, in inches, empty and then filled with water only.
| Aqueon tank | Dimensions (L x W x H, inches) | Empty weight | Filled weight |
|---|---|---|---|
| 20 Long | 30 1/4 x 12 1/2 x 12 3/4 | 25 lb | 225 lb |
| 29 | 30 1/4 x 12 1/2 x 18 3/4 | 40 lb | 330 lb |
| 30 (standard) | 36 1/4 x 12 5/8 x 16 3/4 | 43 lb | 343 lb |
| 30 Breeder | 36 3/16 x 18 1/4 x 12 15/16 | 48 lb | 348 lb |
| 40 Breeder | 36 3/16 x 18 1/4 x 16 15/16 | 58 lb | 458 lb |
The breeder is about 4 inches lower and almost 6 inches deeper than the standard 30. Those 6 inches are the whole story for aquascaping. You can run three planes of rock or wood front to back and still leave open sand at the front. On a 12 inch footprint the midground and background collapse into one line.
The lower height also puts your light closer to the substrate, so carpeting plants such as Monte Carlo and dwarf hairgrass fill in under a mid-range LED that would struggle through 17 inches of water.
Video: George Farmer
Pick the standard 30 if you want tall stems, a back wall of Vallisneria, and fish that use vertical space such as angelfish.
Hardscape depth on an 18 inch base
Slope the substrate from about an inch at the front glass to 4 or 5 inches at the back. The slope adds perceived depth and gives stem plants deeper soil for their roots. The planted tank setup guide covers soil depth, cycling and the first month of trimming.
Set your main stone or wood a third of the way in from one side, with smaller pieces behind it so the layout reads as a slope. Keep the front 4 inches clear.
Stocking a 30 gallon planted tank
Stock by swimming length and floor space. The 36 inch length suits one school of a dozen small tetras or rasboras, and the sand front on a breeder gives eight corydoras real ground to work. Add one centrepiece pair, such as honey gouramis or an Apistogramma pair, plus Amano shrimp for algae.
If you already know what fits in a 20 gallon fish tank, keep the same school sizes and spend the extra room on hardscape instead of a second species.
A 40 gallon breeder shares the exact footprint and adds 4 inches of height and 110 lb of filled weight. If your stand and floor take the load, it gives you the same layout with a taller water column for stems.
Weight, stand and light on a 36 inch tank
Aqueon lists a filled standard 30 at 343 lb and a filled breeder at 348 lb before substrate, rock and equipment. A stand rated for a 40 breeder leaves margin for heavy stone.
Lighting is where the breeder bites back. A single narrow 36 inch fixture over an 18 inch wide tank leaves the front and back strips dim. Choose a wide-spread fixture, or run two narrow bars.