Clown Killifish (Rocket Killi)

Biology and Vision:

They have developed a parietal organ on the top of the head sensitive to changes in light (useful for detecting winged predators like birds). The large eyes positioned very high on the skull allow them to scan the water surface without having to break it.

Spontaneous Reproduction:

You often realize they have bred only when you notice micro-fry resembling 1 mm thick glass pins navigating among the leaves of floating plants. Being so small, the newborns cannot even eat brine shrimp nauplii; for the first few days, their diet consists exclusively of microscopic infusoria and paramecia naturally present in the floating moss.

"Blackwater" and Surface Setup:

Forget the bottom of the aquarium, these fish only live in the top 2 cm of water. The perfect tank has mangrove roots or oak leaves on the bottom to create amber water rich in tannins (slightly acidic pH) and a very dense cover of floating plants (e.g., hanging roots of *Limnobium laevigatum*). This tangle of roots provides shelter, hiding places for the young, and a flat surface to lie in wait.

The Feeding Challenge (Micro-Insectivores):

Being so small and having superior axillary mouths, they almost totally ignore food that sinks mid-water and disdain large flakes. Feeding them long-term with dry food leads to malnutrition. The secret of success with Clown Killis is breeding live insects: cultures of Springtails (Collembola) or wingless fruit flies (Drosophila) to be gently dusted on the water surface, triggering their fantastic snap predatory instinct.

Lid and Current:

Like most Killis, even if they hover lazily, they are capable of explosive jumps to catch a flying insect or escape. An uncovered tank will inevitably end up with dried fish on the floor. The water must be stagnant or imperceptibly moved by an air filter.