Breeding Amano Shrimp

How to breed Caridina multidentata, an amphidromous shrimp whose larvae need brackish water: berried females, hatching, the saltwater larval phase and return to freshwater.

Overview

Caridina multidentata is amphidromous: as Wikipedia explains, oviposition and hatching occur in freshwater, the newly hatched larvae drift to saltwater to develop, and the juveniles then return to freshwater as adults. This life cycle is why breeding is rated advanced, the larvae cannot survive to adulthood in a normal freshwater tank.

Sexing

Females have a more elongated lower row of dots along the body compared with males, which helps tell the sexes apart. A mature female ready to breed carries a green-grey mass of eggs (a saddle, then a berried clutch) beneath her tail.

Egg Carrying & Hatching

After mating, the female carries the developing eggs under her pleopods for roughly 4-6 weeks until they hatch. The eggs are rich in yolk and oval-shaped, which lets the larvae rely on internal nutrition for a while before they must feed. The larvae that hatch are tiny planktonic zoea.

The Brackish Larval Phase

The larvae must be moved to brackish or marine-strength saltwater within a few days of hatching to survive, and it is best done promptly. According to The Shrimp Farm, they pass through multiple zoea stages, and metamorphosis into miniature shrimp takes on the order of 40 days. The larvae graze on diatoms and algae growing on the rearing-container walls.

Return to Freshwater

Once the larvae metamorphose into juveniles that look like miniature adults, they must be transitioned back to freshwater. The change should be gradual, not sudden, to avoid shock.

Common Challenges

Getting the larvae into saltwater quickly, holding stable salinity through the long larval phase, providing enough fine algal food, and managing the gradual transition back to freshwater are the main reasons most freshwater keepers never see Amano shrimp larvae reach adulthood.