90-Gallon High-Tech Iwagumi Aquascape (Advanced)
A 90-gallon Iwagumi: a few stones, one carpet, and a great deal of deliberate empty water. It is a proper display tank with room to build depth. Pressurised CO2, active soil and real light — faster growth, more colour, and a tank that needs you every week. 1 plant species, Seiryu Stone, and 4 livestock groups checked against each other for compatibility — every quantity below sized to 90 gallons and every plant chosen for an advanced.
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Everything below is generated for this 90-gallon Iwagumi build — 1 plant, 4 livestock groups, and gear sized to 90 gallons. The studio does the same for your tank, free.
Hardscape — what to buy and how to place it
Seiryu Stone is blue-grey, sharply angular, cut through with white calcite veins that run the same way on every piece. Seiryu is a carbonate rock, so it slowly raises KH, GH and pH. That suits most community fish and is worth knowing if you are keeping soft-water species — test your KH a fortnight after filling rather than assuming your tap numbers still apply. Keep every stone’s veins running in the same direction; it is the single thing that makes a group read as one broken rock rather than several unrelated ones.
At 90 gallons, plan on seven or more pieces in clearly unequal sizes. An odd count is easier to compose, and one piece should obviously lead — a group of similar-sized pieces spread evenly across the tank is the most common way a first scape goes flat.
Iwagumi is built from named roles, not from a pile. The Oyaishi is the main stone: the largest, set on a third of the tank width rather than the centre, leaning very slightly off vertical. The Fukuishi supports it from the opposite side at roughly two-thirds its size, and the Soeishi is smaller again and sits close to the Oyaishi. Odd numbers only, and no two stones the same size.
Substrate
Aqua soil (e.g. ADA Amazonia / UNS Controsoil), built to about 3–4" 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.
The whole floor of this tank is Glossostigma, so the substrate contour IS the layout — there is no background planting to hide a flat bed. Build a real slope from front to back and let the carpet run up and over it; that rise is what gives an otherwise open tank its depth. Plant in small clumps a couple of centimetres apart and let them spread sideways to meet, rather than packing them in to look finished on day one.
At 90 gallons the substrate is a real purchase, not an afterthought — budget for it early and buy it all at once, because a bed topped up later with a different bag rarely matches.
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. Glossostigma is the tallest thing in this plan at around 1.2", so it sets your back row and everything else steps down in front of it.
Glossostigma is the fast grower here — tiny bright carpet; needs strong light or it grows tall and leggy. 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.
Stocking
This stocking is built to spread through the tank rather than crowd one layer: Cardinal Tetra and Diamond Tetra share the open middle water and Bolivian Ram and Two-banded Apisto share 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 Cardinal Tetra in 6 or more and Diamond Tetra in 6 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.
Bolivian Ram is the centrepiece. Hardier, cooler-tolerant alternative to the German ram; great for beginners to cichlids.
- Cardinal Tetra — Keep Cardinal Tetra in a group of at least 6 — kept in ones or twos they get stressed, shy, and nippy.
- Bolivian Ram — Bolivian Ram is territorial/solitary — best kept as a single specimen.
- Diamond Tetra — Keep Diamond Tetra in a group of at least 6 — kept in ones or twos they get stressed, shy, and nippy.
Two-banded Apisto is semi-aggressive, so give this tank more cover and more broken sight-lines than the plant list alone suggests — territory disputes mostly resolve themselves when a fish can get out of sight. 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 | Oase BioMaster Thermo 350 | ~$280–350 |
| Lighting | Twinstar 1200SP | ~$720–860 |
| Co2 | GreenLeaf Aquarium GLA Regulator + 20lb Cylinder | ~$400–510 |
| Heating | Oase BioMaster Thermo 600 (integrated) | Included with Oase BioMaster Thermo 600 (~$360–450) |
| Substrate | ADA Aqua Soil Amazonia II 9L + Powder | ~$75–98 |
| Fertilizer | ADA Green Brighty Nitrogen + Step 2 | ~$48–65 |
| 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. Keep the photoperiod short, around six hours, while the plants root. |
| 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 carpet should be visibly running now; resist raising the light to hurry it. |
| Months 2–3 | The scape fills in and the routine settles into the schedule below. On a tank this size, get the maintenance rhythm fixed now — a large tank is very stable until it is not, and by then it is a large problem. |
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 36 gallons on this tank — using a tap-fed water changer — at this volume buckets stop being realistic. 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. On a tank this size also check the seals and the stand for damp, because a slow leak here is a floor problem, not a tank problem. |
| 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.
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