Humphead Glass Fish (Parambassis pulcinella)

The pronounced hump this fish develops on its forehead with age comes down to fat and connective tissue deposited under the skin, the same basic mechanism behind the head growths seen in flowerhorn cichlids and a handful of other unrelated species — a case of different fish converging on the same "bigger head reads as bigger fish" display. Underneath the hump it's still built on the same mostly transparent body plan shared across the broader glassfish group.

Care level: Moderate · Temperament: Peaceful, shoaling · Max size: ~5" · Min tank: 30 gal · Diet: Carnivore, live/frozen foods