Cartilage fish are always marine and are always ammonotelic/Ureotetic.

Explanation

### Step-by-Step Solution:

1. **Understanding Cartilaginous Fish**:
- Cartilaginous fish, such as sharks and rays, belong to the class Chondrichthyes. They are characterized by having a skeleton made of cartilage rather than bone.

2. **Habitat**:
- These fish are exclusively marine, meaning they inhabit saltwater environments like oceans and seas.

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