Bare Bottom Advantages
Easier to vacuum waste — siphon directly from the glass.
No anaerobic dead zones from compacted substrate.
Easier to spot illness early (poop color, eggs, dropped scales).
No substrate getting flipped during fish digging.
Bare Bottom Disadvantages
Looks utilitarian, not natural.
Bright reflection from glass can stress the fish. Add a dark background and reduce direct overhead lighting.
No place for live plants (though most flowerhorn keepers do not use live plants anyway — fish dig them up).
- ✦Paint the bottom outside the tank black or dark blue.
- ✦Add a dark backing for color enhancement.
Sand Substrate
Pool filter sand or aquarium sand. Soft on fish belly when resting. Mimics natural lakes/rivers.
Drawback: flowerhorns dig and stir sand constantly. Cleaning takes more effort.
Gravel Substrate
Smooth river gravel. Easy to vacuum. Safer than sand for flowerhorns that dig hard.
Drawback: traps food and waste between pebbles. Vacuum thoroughly weekly.
Safe Decor
Smooth river rocks (not stacked tall — flowerhorns knock them over).
Driftwood: large pieces, weighed down. Soak first.
Avoid: small ornaments (knocked around), plastic plants (chewed up), live plants (eaten/dug up).