Buy me a coffee“Arapaima: The Silent River Predator of Murky Depths”
“Arapaima—armored, air-breathing river hunters that strike from below with sudden, bone-jarring force.”
The arapaima is a large, air-breathing freshwater fish known for its metallic scales, powerful suction-bite, and sudden ambush attacks from beneath the surface, dominating the slow, oxygen-poor rivers of the rainforest through stealth, mass, and precision.
Appearance
The arapaima is a long, muscular freshwater fish covered in heavy, overlapping scales that shimmer like dark metal in sunlight. Its streamlined body tapers into a reddish tail, while its broad head and cavernous, bone-plated jaws allow it to draw prey in with a forceful suction strike.
Behaviour
Generally calm but alert, arapaimas glide slowly through their territory, rising periodically to the surface with a loud whoomph to gulp air into their modified, lung-like swim bladder. When disturbed or hunting, they erupt with a sudden burst of speed, using their body weight and powerful tail to ram or ingest prey before retreating to deeper water.
Habitat
Arapaimas inhabit warm, low-oxygen waters—flooded forests, deep river channels, oxbow lakes, and shaded swamp pools. They favor areas with submerged roots, fallen logs, and silt-heavy currents where they can rest unseen and launch short ambushes.
Modus Operandi
These predators rely on stealth and quick acceleration. They float motionless beneath the surface, then lunge upward to capture prey with a vacuum-powered gulp. When threatened at close range, they thrash violently, using their mass and tough scales to deter attackers. Their need to surface for air can make them predictable, but never harmless.
Motivation
Arapaimas are driven by hunger, territory maintenance, and the instinct to surface regularly for air. They fiercely protect feeding pools, spawning sites, and calm backwaters where their young can develop safely.
Arapaima 5e 2024
Arapaima, Pathfinder
Arapaima 3.5
Arapaima
Large beast, unaligned
Armor Class 14 (natural armor)
Hit Points 82 (11d10 + 22)
Speed 0 ft., swim 40 ft.
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 20 (+5) | 12 (+1) | 15 (+2) | 2 (–4) | 12 (+1) | 5 (–3) |
Saving Throws Dex +3, Con +4
Skills Perception +4, Stealth +3
Damage Resistances bludgeoning from nonmagical attacks
Senses passive Perception 14
Languages —
Challenge 3 (700 XP)
Proficiency Bonus +2
TRAITS
Air-Breather
The arapaima must surface every 10 minutes to gulp air into its swim bladder. It suffocates if prevented from doing so.
Burst Swimmer
If the arapaima swims at least 20 feet straight toward a creature immediately before making a Bite attack, that attack deals an extra 10 (3d6) damage.
Still-Water Camouflage
The arapaima has advantage on Dexterity (Stealth) checks made to hide in murky, silt-heavy, or low-light water.
Vacuum Maw
When the arapaima hits a creature with its Bite, the target must succeed on a DC 15 Strength saving throw or be pulled up to 10 feet toward the arapaima before the damage is resolved.
Surface Lunger
When the arapaima surfaces to breathe, it can immediately move up to 10 feet without provoking opportunity attacks.
ACTIONS
Multiattack
The arapaima makes one Bite attack and one Tail Slam attack.
Bite
Melee Weapon Attack: +7 to hit, reach 5 ft., one target.
Hit: 19 (3d8 + 5) piercing damage.
The target must succeed on a DC 13 Constitution saving throw or have its speed reduced by 10 ft. until the end of its next turn.
Tail Slam
Melee Weapon Attack: +7 to hit, reach 10 ft., one target.
Hit: 13 (2d8 + 5) bludgeoning damage.
A Medium or smaller creature must succeed on a DC 15 Strength saving throw or be knocked prone (in the water).
Suction Surge (Recharge 5–6)
The arapaima creates a powerful underwater vacuum.
Each creature in a 15-foot cone must make a DC 14 Strength saving throw, taking 10 (3d6) bludgeoning damage on a failed save or half as much on a success.
A creature that fails the save is also pulled up to 15 feet toward the arapaima.
REACTIONS
Sudden Breach
When a creature enters the water within 10 feet of the arapaima, it surges upward.
The arapaima moves up to 10 feet and makes one Bite attack against that creature.
BONUS ACTIONS
Surface Gulp
The arapaima surfaces for air, gaining 10 temporary hit points.
If Suction Surge is recharged, it may use it immediately after gulping.
LEGENDARY ACTIONS
(Optional; appropriate for a boss-of-the-river version.)
The arapaima can take 1 legendary action, choosing from the options below.
Move. The arapaima swims up to half its speed.
Tail Flick. The arapaima makes one Tail Slam attack.
TACTICS
The arapaima prefers ambush hunting:
- Waits motionless beneath murky water, hidden by camouflage
- Opens combat with a Burst Swimmer Bite for maximum damage
- Uses Tail Slam to unbalance foes or knock swimmers from boats
- Surfaces strategically, using Surface Lunger to reposition safely
- Employs Suction Surge to drag enemies off the shore or into striking range
- Retreats into deeper water when bloodied, using the river’s shadows to reset the fight
Its combat behavior is simple but highly effective: close distance fast, disrupt balance, isolate targets, and drag them under.
Lore
Arapaimas are large, air-breathing fish that thrive in warm, oxygen-poor rivers where few other predators can survive. Their heavy scales and motionless drift make them nearly invisible beneath murky water until they strike. Riverfolk recognize their deep, resonant whoomph as they surface to breathe—a sound equal parts warning and omen. Though not malicious, arapaimas are fiercely territorial, overturning canoes or ramming intruders that wander too close to their feeding or spawning grounds. Many druids regard them as vital river custodians, quietly maintaining balance in the drowned forests and shadowed channels they call home.
Arapaima
Large Animal (Aquatic), Unaligned
Defense
AC: 17, touch 10, flat-footed 17 (+7 natural)
HP: 85 (10d10+30)
Fort: +8 | Ref: +3 | Will: +1
Defensive Abilities: Hard Scales (+2 natural armor vs. nonmagical attacks)
Offense
Speed: Swim 40 ft.
Melee: Bite +12 (3d8+5 plus suction), Tail Slam +12 (2d8+5, prone on Medium or smaller)
Special Attacks: Suction Maw, Burst Swim, Surface Lunge
Spell-Like Abilities: None
Statistics
Str 20 | Dex 12 | Con 16 | Int 2 | Wis 12 | Cha 5
Base Attack/Grapple: +10/+15
Feats: Power Attack, Improved Bull Rush, Weapon Focus (Bite), Combat Reflexes
Skills: Perception +9, Stealth +5 (in murky water)
Languages: —
SQ: Air-Breathing, Still-Water Camouflage, Vacuum Maw, Surface Lunger
Special Qualities: Blood Sense (detects prey in water within 30 ft.), Low-Light Vision
Combat
The arapaima hides in murky water, striking suddenly with Burst Swim Bite and pulling targets with Suction Maw. Tail Slam controls foes, while Surface Lunge allows repositioning after surfacing. It retreats to deeper water when wounded, using camouflage to reset the fight.
Special Abilities
- Air-Breathing (Ex): Must surface every 10 minutes or suffocate.
- Burst Swim (Ex): Swimming at least 20 ft. straight toward a target adds +3d6 damage on next Bite.
- Vacuum Maw (Ex): Bite can pull a target up to 10 ft. (DC 15 Strength save negates).
- Still-Water Camouflage (Ex): +4 bonus on Stealth in murky/silty water.
- Surface Lunge (Ex): After surfacing, may move 10 ft. without provoking attacks of opportunity.
Role & Lore
Role: Apex freshwater predator, territorial ambusher, ecosystem regulator
Lore: Arapaimas dominate oxygen-poor rivers, using air-breathing ability to survive where other predators cannot. They glide silently beneath murky water and strike suddenly with massive jaws. Local riverfolk respect and fear them; druids see them as guardians of drowned forests and slow rivers.
CR: 5 | XP: 1,600
Arapaima
Large Animal (Aquatic), Unaligned
Hit Dice: 10d8+30 (75 hp)
Initiative: +1
Speed: 0 ft., swim 40 ft.
Armor Class: 17 (+7 natural), touch 10, flat-footed 17
Base Attack/Grapple: +10/+15
Attack: Bite +12 melee (3d8+5 plus suction)
Full Attack: Bite +12 melee (3d8+5 plus suction) and Tail Slam +12 melee (2d8+5)
Space/Reach: 10 ft./5 ft. (Bite), 10 ft. (Tail Slam)
Special Attacks: Suction Maw, Burst Swim, Surface Lunge
Special Qualities: Air-Breathing, Still-Water Camouflage, Blood Sense, Low-Light Vision
Saves: Fort +8, Ref +3, Will +1
Abilities: Str 20, Dex 12, Con 16, Int 2, Wis 12, Cha 5
Skills: Perception +9, Stealth +5 (in murky water)
Feats: Power Attack, Improved Bull Rush, Weapon Focus (Bite), Combat Reflexes
Challenge Rating: 5
Treasure: None
Alignment: —
Special Abilities
Air-Breathing (Ex): Must surface every 10 minutes to breathe air or begin to suffocate.
Burst Swim (Ex): When swimming at least 20 ft. straight toward a target, the next Bite attack deals +3d6 damage.
Vacuum Maw (Ex): Bite attack can pull a target up to 10 ft. toward the arapaima. Target may make a DC 15 Strength check to resist.
Still-Water Camouflage (Ex): +4 racial bonus on Stealth checks in murky or silty water.
Surface Lunge (Ex): After surfacing, the arapaima may move up to 10 ft. without provoking attacks of opportunity.
Blood Sense (Ex): Detects injured creatures in water within 30 ft.
Combat Tactics
- Ambush Predator: Hides motionless in murky water until prey enters striking range.
- Opening Attack: Uses Burst Swim Bite to deal maximum damage and pull prey with Vacuum Maw.
- Control: Uses Tail Slam to knock Medium or smaller foes prone, limiting movement.
- Positioning: Surfaces strategically and uses Surface Lunge to reposition safely.
- Retreat: Withdraws to deeper water when wounded, relying on camouflage to reset the engagement.
Lore
Arapaimas are apex freshwater predators that dominate oxygen-poor rivers, relying on their lung-like swim bladder to survive where other predators cannot. These heavy, armored fish glide silently beneath murky waters and strike with sudden force. Local riverfolk respect their power, and druids often regard them as guardians of drowned forests and slow-moving rivers. Their distinctive whoomph breath signals the presence of a massive predator rising to the surface.