Substrate and river rock: the layer everything else sits on
Substrate is chosen last and matters first, because everything in the tank rests on it.
Depth
Around two inches suits most decorative setups — enough to bed plants and ornaments, shallow enough to avoid anaerobic pockets underneath.
Deeper is only needed for heavily rooted live planting.
Grain size and fish
Very fine sand suits fish that sift it; larger gravel and river rock suit tanks where debris should stay on top to be siphoned.
Rounded stone is kinder to any fish that spends time on the bottom than sharp crushed gravel.
Rinse before it goes in
Even washed rock carries dust that will cloud a tank for days. Rinse it in batches in a bucket until the water runs clear.
This is tedious and it is the difference between a clear tank on day one and a cloudy one all week.
Colour and how fish look
Pale substrate makes fish appear washed out; darker substrate brings out colour. Multicolour gravel is a preference and a strong one either way.
If the fish are the point, darker is usually the better backdrop.
Weight and glass
Stone is heavy. Place larger rock on a thin substrate bed rather than dropping it onto bare glass, and place it before filling.
Rockwork added to a full tank is how base glass gets chipped.
Cleaning around it
Debris settles on top of larger rock rather than sinking into it, which makes siphoning easier than with sand.
That is the practical argument for river rock in a decorative tank.
Stability
Anything stacked should be stable enough that a fish cannot undermine it. Bed the bottom pieces into the substrate rather than resting them on top.
Digging species will test this, so build as if they will.
Four products that show the range
The least expensive way in: Wonfly Pink Floating Diver Aquarium Ornaments, 2-Pack Resin Fish Tank Decoration at $5.99. Listed with its own specification table, so the dimensions and what is in the box are on the page rather than in a description.
A step up from the basics: EMUTOL 5″ Aquarium Underground Tunnel, Dual-Entrance Fish Tank Cave for Betta & Shrimp at $8.59. Listed with its own specification table, so the dimensions and what is in the box are on the page rather than in a description.
A middle-of-the-range option: Litewoo Blue Ceramic Shell Hideout for Betta Fish & Small Aquariums at $13.99. Listed with its own specification table, so the dimensions and what is in the box are on the page rather than in a description.
The most substantial option: FISHNOSH 1-Count Aquarium Cave Decor, Natural Wood-Like Fish Hideout for Tanks at $19.99. Listed with its own specification table, so the dimensions and what is in the box are on the page rather than in a description.
What it costs
Across the 22 items currently listed, prices run from $5.99 to $19.99, with the middle of the range around $9.98. That spread is worth knowing before you start comparing, because the cheapest and dearest options here are usually not the same kind of product at all.
Shipping is a flat $4.49 per order and free once the order reaches $29.00, which is set out in full on the Shipping Policy page.
Coming in instead
Pacific Aquarium & Plant Inc. is at 46 Delancey St, New York, NY 10002, open Mon–Sun: 10:00 AM–6:00 PM. If you would rather look at something before buying it, call +1 212-995-5895 and we will put it aside for you.
Anything already ordered can be followed on the order tracking page.
Questions that come up with this
Is everything aquarium-safe?
Yes. What we list is sold for tank use and is inert in water. Rinse before placing, and never use soap.
How fast do orders go out?
One to two business days to pack, then two to five business days across the United States.
What is the postage?
Flat $3.95 per order, and free once the basket reaches $29.00.
The FAQ page covers the rest.
Where this sits in the shop
Pacific Aquarium & Plant Inc. groups its range into 5 sections, so it is usually quicker to start from the group than to scroll the whole shop. These are the ones with stock on the shelf right now:
- Caves and Hideouts — 11 items
- Shipwrecks and Castles — 7 items
- Ornaments — 2 items
- Artificial Plants — 1 item
- Substrate and Stone — 1 item
If none of those is obviously right, the full shop lists everything on one page.
Related reading
Other pieces in this journal that cover neighbouring ground:
- Rinsing new aquarium decor before it goes in the tank
- Choosing a cave or hideout that a betta will actually use
- Silk plants and why they beat plastic in a small tank
- Aquascaping a small tank so it does not look crowded
The full journal index lists everything we have written so far.
In short
Substrate is chosen last and matters first, because everything in the tank rests on it. If you want to talk it through rather than read about it, +1 212-995-5895 reaches the shop during opening hours, and the contact page has everything else.