Siltjaw

Ecology

The Siltjaw is a mid-sized ambush predator of slow water and mud margins -- the apex still-water hunter in systems too shallow or too silted for the Deepfin and too warm and mud-heavy for the Bladefin. Its entire behavioral and morphological profile is organized around one moment: the transition from total stillness below the surface to the grip of the Bite in under a second. The Hold Breath capacity of 15 minutes allows it to wait motionless in water too turbid for visual detection, and its Stealth +5 in that environment consistently beats the Passive Perception of most targets at approach distances. By the time the animal is visible, the strike has either happened or is not going to happen.

The Bite applies the Grappled condition; the Drag action that follows on subsequent turns pulls Grappled targets prone and into water where the geometry and movement penalties compound the problem. This is a sequential encounter design: Bite → Grapple → Drag → hold in place while the target drowns or the party gets them free. The Siltjaw is not trying to kill at range or out-maneuver a combat-capable group; it is trying to get one target into its element and keep them there.

They are not social animals. Multiple Siltjaws in the same waterway occupy distinct zones and avoid each other outside mating season. The practical effect is that encounters in large estuarine systems can involve multiple animals; knowing one is in a ford does not mean the next ford a half-mile upstream is clear.

The Miasm saturation in slow deltaic water runs higher than in fast-moving river systems, and Siltjaws in those zones develop the secondary calcification that the Tidecrab shows in coastal populations -- mineral-dense scales with a surface texture that looks, and is, harder than the smooth juvenile carapace. The visual indicator is a slight green-grey iridescence along the dorsal ridge, which experienced guides treat as a warning sign of high-saturation water.