Categorize these animals by type.

Goldfish, Elephant, Spider, Goose
Goldfish: Fish
Elephant: Mammal
Spider: Arachnid
Goose: Bird
Complete the following task based on the instruction and optional input provided.### Instruction:
Categorize these animals by type.

Goldfish, Elephant, Spider, Goose

### Output:
Goldfish: Fish
Elephant: Mammal
Spider: Arachnid
Goose: Bird