Which of the following pairs consists of commonly used larvivorous fish for urban mosquito control?

• A. Tilapia nilotica and Carassius auratus (goldfish)
• B. Poecilia reticulata (guppy) and Tilapia nilotica
• C. Gambusia affinis (mosquito fish) and Poecilia reticulata (guppy)
• D. Tilapia nilotica and Gambusia affinis (mosquito fish)

Answer: (C)

The main idea here is identifying two fish that are commonly used to eat mosquito larvae in urban water sources. Gambusia affinis, the mosquito fish, is a classic choice because it tolerates a range of water conditions and voraciously consumes mosquito larvae, helping to keep larval populations low in standing water like ponds, ditches, and containers. Poecilia reticulata, the guppy, is also used in urban settings due to its small size, ease of care, rapid reproduction, and willingness to feed on larvae in smaller or more controlled habitats, making it a practical partner for larval control in many urban situations.

Tilapia nilotica, while capable of consuming some larvae, typically requires larger spaces and more specific conditions, making it less practical for routine urban container or small-pond control. Goldfish can eat larvae, but they are not the standard choice in mosquito-control programs because of care needs and ecological concerns if released. Taken together, Gambusia affinis and Poecilia reticulata are the pair most commonly used for urban larval control.