snakefish
鮀 centers on a specific type of fish: the snakefish. The meaning is narrow and refers directly to this animal.
鮀 combines 魚 (fish) with 它, which likely contributes the sound. The exact historical development is uncertain, but the structure points to a phono-semantic compound for a type of fish.
The left side is a fish 魚, and the right side 它 looks a bit like a snake. Picture a fish with a snake-like body: that's the snakefish.
For タ, imagine a snakefish wearing a tiny top hat: 'ta' as in 'ta-da!' when it appears. The hat helps you remember タ.