Best Bottom-Dwelling Fish for Keeping the Lower Tank Level Active

Most beginner aquariums are filled with mid-water schooling fish, leaving the bottom level empty and bare. Bottom-dwelling fish solve this instantly — they clean the substrate, explore caves and driftwood, and bring constant gentle activity to the lower third of the tank. Here are the best options for Singapore freshwater aquariums.

Why You Need Bottom-Dwellers

Bottom-dwelling fish serve a practical function: they consume uneaten food and organic debris before it decomposes and spikes ammonia. Beyond utility, they add visual interest to a zone that mid-water fish rarely visit.

1. Corydoras Catfish

Corydoras are the most popular bottom-dwellers in the hobby for good reason. They are completely peaceful, social (keep 6+), and actively sift through substrate all day. Over 170 species exist — from the common bronze cory to the striking sterbai and the tiny pygmy cory for nano tanks.

Best for: Any community tank | Tank: 40+ litres | Temp: 22–26°C

2. Kuhli Loach

Kuhli loaches are eel-like, orange-and-black striped fish that burrow into fine sand and squeeze into the tightest gaps in driftwood and roots. They are nocturnal but become more active over time in established tanks. Keep 3 or more.

Best for: Planted tanks with fine sand | Tank: 40+ litres | Temp: 24–30°C

3. Bristlenose Pleco

The bristlenose pleco is a compact, algae-eating catfish that stays under 15 cm — unlike common plecos that outgrow most home tanks. Males develop distinctive bristles on their snout. They rasp algae from glass, wood, and large plant leaves.

Best for: Tanks with driftwood and algae | Tank: 60+ litres | Temp: 20–27°C

4. Otocinclus Catfish

Otos are tiny (3–5 cm) algae eaters that cling to plants and glass rather than the substrate. They are ideal for planted tanks where corys might uproot delicate foreground plants. Keep them in groups of 6+.

Best for: Planted tanks | Tank: 40+ litres | Temp: 21–27°C

5. Hillstream Loach

Hillstream loaches are flat, sucker-mouthed fish adapted for fast-flowing streams. In aquariums they cling to smooth rocks and glass panels, rasping biofilm and algae. Their alien appearance makes them a conversation piece.

Best for: High-flow tanks, hillstream biotopes | Tank: 60+ litres | Temp: 20–24°C

6. Pygmy Cory (Corydoras pygmaeus)

Pygmy corys are only 2–3 cm long and spend as much time in the mid-water column as they do on the bottom. They are ideal for nano planted tanks where standard-sized corys would be too large.

Best for: Nano tanks 20–40 litres | Temp: 22–26°C

Bottom Substrate Recommendations

• Fine sand: Best for corys and kuhli loaches — coarse gravel can damage barbels
• Smooth substrate: Hillstream loaches need smooth rocks or bare glass sections
• Driftwood: Essential for plecos, which rasp wood as a dietary supplement

Avoid Overcrowding the Bottom Layer

The bottom zone has limited real estate. A 60 litre tank can comfortably support a group of 6 corydoras OR a bristlenose pleco, but not both along with kuhli loaches. Plan bottom stocking carefully.

Explore our full range of bottom-dwelling livestock available for delivery across Singapore.