20-Gallon High-Tech Nature Aquascape (Intermediate)
A 20-gallon Nature Aquarium — a landscape rather than a display, built around one off-centre focal mass with the planting stepping away from it. It is a standard tank size, and the easiest bracket to get right. Pressurised CO2, active soil and real light — faster growth, more colour, and a tank that needs you every week. 6 plant species, Spiderwood and Dragon Stone, and 4 livestock groups checked against each other for compatibility — every quantity below sized to 20 gallons and every plant chosen for an intermediate.
Generate this exact design in the studio →
More than a design — your whole aquarium, handled
Everything below is generated for this 20-gallon Nature build — 6 plants, 4 livestock groups, and gear sized to 20 gallons. The studio does the same for your tank, free.
Hardscape — what to buy and how to place it
Spiderwood is pale bleached azalea root — a compact knot with many fine roots spreading out of it and tapering to hair-thin ends. Tannin release is mild and short-lived, so the water stays largely clear. Two things happen early and both are normal: it floats until it waterlogs, so weight it down for the first week or two, and it grows a white fuzzy biofilm within days of going under. The biofilm is a harmless fungus that feeds on the wood sugars — shrimp, otocinclus and snails eat it, and it disappears on its own within a few weeks.
Dragon Stone is warm ochre and deeply pitted, full of hollows and honeycombed pockets. Dragon Stone is baked clay and chemically inert, so it will not move your pH or hardness in either direction. Rinse and scrub it hard before it goes in — dry Ohko sheds a fine clay dust that will cloud the water for days. The hollows are planting pockets: press moss or a small epiphyte into them and the stone disappears into the scape as it grows.
Pairing Spiderwood with Dragon Stone works because they do different jobs: the stone anchors the base and holds your substrate contour, and the wood carries the height and the movement above it. Let them touch — wood resting into a stone, sand banked against both — so the two read as one structure rather than two separate features sharing a tank.
The most useful check is the silhouette. Squint at the hardscape before you plant, and if the outline is a flat lump or a symmetrical hill, move something. You want an uneven top edge, one clear high point off to one side, and at least one dark recess for the eye to fall into.
Substrate
Aqua soil (e.g. ADA Amazonia / UNS Controsoil), built to about 2–3" and sloped higher at the back. Active soil buffers soft, slightly acidic water and feeds roots. Slope higher at the back for depth.
Fresh aqua soil leaches ammonia for the first one to three weeks. That is normal and it is also why you do not stock a high-tech tank early: run it, change a good volume of water two or three times in that first fortnight, and wait for ammonia and nitrite to read zero before any livestock goes in.
Because this plan carpets the foreground, keep the front of the substrate shallow and level — around an inch is plenty — and save the depth for the back. Carpets are planted into a flat bed in small clumps a couple of centimetres apart, and they spread sideways to meet; planting them dense enough to look finished on day one wastes plants and traps debris.
Melon Sword is a root feeder rather than a water-column feeder, so it wants depth and a root tab more than it wants dosing. Give that part of the bed the extra depth.
Plant list & placement
Plant back to front, into damp substrate with the tank only part-filled — it is far easier than fighting buoyancy in a full tank. Melon Sword is the tallest thing in this plan at around 16", so it sets your back row and everything else steps down in front of it.
Riccia is the fast grower here — bright pearling carpet when tied down; needs high light/CO2. Expect to be cutting it weekly once it establishes. Top the stems, replant the healthy tops in the same group and discard the old bases; a stem bed replanted from tops stays dense, while one left to grow on goes bare at the bottom.
Hymenasplenium obscurum is an epiphyte and must never be buried. Tie or glue the rhizome onto your hardscape and leave it fully exposed — a buried rhizome rots, and it is the single most common way a beginner loses an Anubias or a Java fern. Only the roots may touch the substrate.
Group the stems rather than spacing them out. Limnophila aromatica and Ludwigia arcuata each want to be planted as a block of stems an inch or so apart, cut to slightly different heights so the group fills in with a rounded top instead of a flat hedge.
Stocking
This stocking is built to spread through the tank rather than crowd one layer: Celestial Pearl Danio works the open middle water, Peaceful Betta works every level and Three-Striped Apisto works the floor. A tank where every fish occupies the same band looks half-empty even when it is fully stocked, and the fish themselves compete more.
Keep Celestial Pearl Danio in 8 or more. These are not decorative numbers — a shoaling fish kept in threes spends its life stressed, colours down and hides, and people then conclude the species is dull. The counts in the list above are already scaled to this tank.
Peaceful Betta is the centrepiece. Wild betta far more peaceful than splendens; can sometimes be kept in groups.
Red Racer Nerite Snail is the clean-up crew, and in a planted tank it earns its place — grazing biofilm and soft algae off the hardscape and leaves faster than you can. Add it last, once the tank has some algae to eat, and drip-acclimatise rather than dumping the bag in.
- Celestial Pearl Danio — Keep Celestial Pearl Danio in a group of at least 8 — kept in ones or twos they get stressed, shy, and nippy.
- Peaceful Betta — Keep only ONE male Betta — males fight to the death. One male with several females works only in a large, heavily planted tank.
- Three-Striped Apisto — Three-Striped Apisto is territorial/solitary — best kept as a single specimen.
Peaceful Betta has trailing fins, so the real constraint on this tank is fin-nipping — every other species here was tested against that specifically and anything that has been credibly reported as a nipper was excluded, not merely flagged. Every pairing was run through Skapelab’s compatibility engine and anything returning even a caution was swapped out rather than published. Check any substitution you make there before you buy.
Equipment
| Category | Recommendation | Notes |
|---|---|---|
| Filtration | Fluval 207 Canister Filter | ~$105–140 |
| Lighting | Chihiros WRGB II 30 | ~$105–140 |
| Co2 | CO2Art Pro SE Series Regulator + 5lb Cylinder | ~$145–185 |
| Heating | Hygger 200W Titanium Heater with Controller | ~$32–48 |
| Substrate | Mr. Aqua Aquarium Soil 9L | ~$32–46 |
| Fertilizer | Estimative Index DIY NPK Dry Ferts Kit | ~$28–45 |
| Testkit | API Freshwater Master Test Kit | ~$28–42 |
| Water treatment | Seachem Prime 500ml | ~$12–20 |
| Bacteria | Seachem Stability 250ml | ~$8–14 |
What the first two months look like
| Week 1 | Hardscape in, planted, filled and running with no livestock. CO2 comes on an hour before the lights and off an hour before they go out; aim the drop checker at a green, never yellow. Your Spiderwood will still be trying to float, so keep it weighted or clipped down until it waterlogs. |
| Weeks 2–4 | Cycling, and the ugly phase. Brown diatom dust on the glass and hardscape is normal in a new tank and passes on its own once silicates are used up; the fresh soil is also still releasing ammonia, so keep changing water. Some plants will melt back and regrow in their submersed form — that is conversion, not death, so trim the mush and leave the roots. Do not stock until ammonia and nitrite both read zero. |
| Weeks 4–6 | Stocking begins, a few animals at a time with a fortnight and a water test between additions. The first real trim happens somewhere in here, and the tank stops looking newly planted. |
| Months 2–3 | The scape fills in and the routine settles into the schedule below. Judge the design now rather than on day one; a planted tank is not finished until it has grown into itself. |
Care schedule
| Daily | Feed lightly — as much as they clear in a minute or two — and take ten seconds to count heads and look at the plants. Check the drop checker is green before the lights come on. |
| Weekly | 40% water change — about 8 gallons on this tank — using a siphon and a bucket. Dose your macros and micros after the change, not before. Wipe the glass and check the CO2 cylinder pressure. |
| Monthly | Rinse filter media in old tank water — never under the tap, which kills the bacteria colony you spent six weeks growing. Test KH, GH, pH and nitrate. Check for anything the weekly routine keeps missing behind the hardscape. |
| Every few months | Replace the CO2 diffuser membrane, check the regulator has not crept, and pull the deepest stems for a hard replant. Lights lose output long before they fail — plan on replacing LEDs or bulbs on a schedule, not on symptoms. |
Make it yours
This is a starting point. Open it in the studio to swap plants, resize to your tank, and get a hand-illustrated render, placement diagram, and shopping list — free.
Start this build →