Least Killifish
Least Killifish are native to the coastal southeastern US, inhabiting shallow ponds and cypress swamps with densely vegetated slow-moving water. Despite the name "killifish" they actually belong to the Poeciliidae family which includes other live-bearers such as guppies and mollies. Heterandria means "different male" referring to their unique reproductive organ (gonopodium). Formosa means "beautiful." Kept since the beginning of the aquarium hobby (early 1800s, it is one of the first fish (along with goldfish) kept without the benefit of electric gadgets (pumps, filters, lights, etc).
- Scientific name: Heterandria Formosa
- Size: 0.75 to 1 inch
- Lifespan: 1 to 2 years
- Water parameters:
- pH range: 6.2 to 7.8
- Temperature range: 68F to 78F
- Water hardness: 5 to 16 dGH (90-286 ppm), 4 to 7 dKH (72-125 ppm)
- Stability, consistency more important than chasing any "perfect" numbers
- Diet: Omnivorous, flake food, dried or frozen baby brine shrimp or daphnia, well-rounded diet enhances health and colors, do not feed on algae
- Breeding: livebearers that reproduce continuously, small spawns daily rather than periodic large spawns (superfetuation--developing fry at different stages)
- Temperament: Peaceful, schooling fish, like to be in groups, but plenty of hiding places in hardscape and plants are desirable
- Water flow: Coming from moving waters, they like gentle yet thorough water flow, well oxygenated but not turbulent
- Filtration: They like clean water with proper balance of nutrients, oxygen, CO2, moderate light, like most aquatic plants, weekly 25% water changes, monitor water conditions regularly