Your answer would likely be "fish" - but there are several ways of thinking about the question!
Biologically, the fish is the only one of the four without a hard shell.
By language, fish is the only one without the letter "L".
There are probably other answers too - these were just off the top of my head, but the biological answer is the most obvious and likely one.
Cowboys loved a colorful phrase! This meant an eccentric person. A hermit would be considered an odd fish.
Eat the even numbered fish.
James Kennedy.
An odd or eccentric person.
Odd one is: Fish (can't live outside water!)Frog, Tortoise, Crab - can survive both in water as well as on land
guitar
Cockles look like two ruffles potato chips placed together in the shape of a clam. (I know this sounds odd, but it is the most accurate description I can come up with). cockles almost look like a clam but it can be pretty!!!!!!!you can almost tell the difference between them.
The barreleye fish is also known as the spookfish. This odd looking fish can get up to 6 inches (15 centimeters) long.
It's an odd-looking, Saltwater Fish that is used by McDonalds in theie Fillet-o-Fish Sandwich. It's been in the news because they are being over-fished
an eel is a vertebrates all fish no matter how odd are vertebrates
The dolphin is a mammal.
She had a pair of eels named Flotsam and Jetsam.