Polypterus Bichirs Thrive When Their Predatory Nature and Escape Skills Are Designed Around, Not Ignored
Polypterus bichirs are rewarding, durable fish in the right hands, but they are not generic community oddballs. Adult size, diet, cover, and tankmate vulnerability all need realistic planning.
Bichir keeper priorities over time
Care Area
| Care Area | Solid Bichir Practice | Why It Helps | Bad Shortcut |
|---|---|---|---|
| Surface access | Leave the fish unobstructed access to the air-water interface | Bichirs are facultative air breathers | Designing decor or covers that trap them away from the surface |
| Tankmates | Use similarly robust fish that cannot be swallowed easily | Reduces predation risk and stress | Relying on juvenile size to judge compatibility |
| Environment | Use cover and calm resting areas | Supports natural behavior and confidence | Bright, exposed tanks with nowhere to hide |
| Security | Treat the lid as part of life support | Prevents fatal escapes | Assuming a heavy-bodied fish cannot climb or wriggle out |
Polypterus Bichir Checklist
| Prioritize floor space and lid security over novelty décor | |
| Expect small fish and shrimp to be prey candidates | |
| Feed species-appropriate foods without turning the tank into a waste sink | |
| Reassess compatibility again as the bichir grows | |
| Assume juvenile bichir behavior predicts harmless adult behavior | |
| Leave open-top gaps because the fish looks too clumsy to escape |
Bichir success usually comes from respecting the fish as a specialized predator with unusual habits, not from trying to force it into a standard peaceful-community template.
A bichir that stops eating, shows abrasions, or spends abnormal time stressed at the surface may be signaling water-quality issues, unsuitable tankmates, or a setup that no longer fits its size.
Polypterus (Bichir) Care: The Prehistoric Living Fossil in Your Aquarium
Polypterus species (family Polypteridae) are among the most ancient fish lineages still alive -- their ancestors branched from the main fish evolutionary tree over 350 million years ago. They breathe both through gills and through a primitive lung-like organ, meaning they must access the water surface regularly or they will drown. They have articulated pectoral fins used for walking along the substrate that resemble an early tetrapod's limbs. They are also among the most durable and adaptable fish in the freshwater hobby, tolerating a wide range of water conditions that would stress or kill other species. The combination of prehistoric appearance, behavioral interest, and genuine hardiness makes bichirs underappreciated gems for aquarists seeking something unusual.
| Species | Adult Size | Min. Tank | Notes |
|---|---|---|---|
| P. senegalus (Senegal) | 12–14 in | 55 gal | Best beginner; most available |
| P. delhezi (Armored) | 14–16 in | 75 gal | May bite tankmates |
| P. ornatipinnis (Ornate) | 18+ in | 125 gal | Striking pattern; intermediate |
| P. endlicheri (Saddled) | 24 in | 125+ gal | Largest; advanced keepers only |
Species Overview
The most commonly available Polypterus species:
Polypterus senegalus (Senegal bichir) -- the most popular and smallest common species, reaching 12-14 inches. Light grey with variable spotting. The best starting species for bichir newcomers.
Polypterus delhezi (Armored bichir) -- strongly patterned with dark saddle markings on a grey-green body. Reaches 14-16 inches. More aggressive than senegalus; may bite tank mates.
Polypterus ornatipinnis (Ornate bichir) -- the most visually striking of the common species; bold black-and-yellow reticulated pattern. Reaches 18+ inches. More expensive and harder to find than senegalus.
Polypterus endlicheri (Saddled bichir) -- one of the largest and most robust species, reaching 24 inches. Substantial tank requirements; a dedicated species tank or large aggressive community is appropriate.
Tank Requirements
Tank size scales with the adult size of the chosen species. Senegal bichirs: minimum 55 gallons for 1-3 individuals. Ornate or Endlicheri bichirs: 125+ gallons for adults. Bichirs are primarily bottom dwellers that patrol the substrate; tank length and footprint matter more than height. Soft sand substrate (they glide on their belly fins across the substrate and are prone to fin abrasion on gravel) and generous hiding spaces (PVC pipe, rock caves, driftwood) reduce stress and territorial conflict when keeping multiple individuals.
Secure the lid: bichirs use their pectoral fins to "walk" out of open-topped tanks and are frequently found on the floor. A heavy, well-fitted lid is non-optional. They will also exploit any gap around filter outputs or cord pass-throughs.
Water Parameters
Bichirs are remarkably tolerant of variable water chemistry -- they are native to African rivers and floodplains that experience seasonal variation in pH, temperature, and hardness. Acceptable ranges: pH 6.5-8.0, temperature 75-82 F, soft to moderately hard water. They are not sensitive to nitrate accumulation in the way that discus or rays are, but standard aquarium maintenance (weekly 25-30% water changes) keeps them in optimal condition.
Diet
Bichirs are carnivores with poor eyesight -- they hunt primarily by smell and pressure-wave detection rather than vision. Live or fresh food is strongly preferred initially; many bichirs can be transitioned to frozen food with patience. Suitable foods: frozen bloodworms, prawn, earthworms, mussel, white fish fillet. Most bichirs can be trained to accept carnivore sinking pellets over time. Feed 2-3 times per week for adults; juveniles daily. Remove uneaten food after a few hours to prevent water quality degradation.
Sources
- Moyle PB, Cech JJ. Fishes: An Introduction to Ichthyology, 5th ed., 2004 -- Polypteridae
- Fishbase.org -- Polypterus species distribution and parameter data
- Seriously Fish (www.seriouslyfish.com) -- Polypterus species profiles