Bluegill is a game fish found in eastern and central North America. These freshwater game fish breed in shallow sections of rivers and lakes, as water temperatures reach 65 degrees Fahrenheit. The male bluegill constructs and guards a nest in the substrate to which females are attracted. Aquarium bluegills spawn if the water temperature is correct and they consume live food. As bluegills, also known as bream, are native fish, it is important to check your state's laws on size limitations before taking bluegills from any local body of water. Harvest regulations do not exist on the majority of lakes throughout the United States.
Bluegills are egg-layers. Eggs and milt -- the liquid containing the sperm -- are released into the water over a pit in the substrate, which the male fish has constructed. The eggs are fertilized as they fall toward the gravel and remain in the nest during their incubation period. The male usually guards both his nest and the newly hatched fry. The substrate in a bluegill-breeding aquarium should be small and rounded, as the male builds his nest by moving gravel in its mouth.
Temperature and Water Parameters
The water temperature in your bluegill breeding aquarium should range from 64 to 75 degrees. Bluegill prefer a neutral pH of 0.7 and although the adult fish are hardy, fry and juvenile fish do not grow correctly in acidic water. Aquarists use a simple dip-and-read pH test kit to determine acidity and alkalinity in the aquarium and a booster agent to correct the pH, if required. Connect a canister or hang-on filter to the aquarium to maintain optimal water quality.
Small bluegills in your aquarium may adopt a specific reproductive behavior and become what is termed “sneakers.” The sneakers mature at a much smaller size when compared to standard males. Breeding males allow sneakers close to the nest, mistaking them for females. Sneakers then release their milt at the same time that the mating pair is spawning, fertilizing existing eggs. The sneaker thereby succeeds in breeding without having to establish a nesting site or guarding the eggs.
Individual bluegill males may become stressed in the confines of an aquarium and eat their young. Captive spawned bluegill fry no longer require protection from the male and the aquarist should remove adult bluegills from the breeding aquarium after the eggs are fertilized. Newly hatched bluegill fry feed on zooplankton. Aquarists can propagate infusoria, or microscopic aquatic organisms, by collecting pond water in a 10-gallon plastic bucket. The natural population of infusoria in this water breeds rapidly and feeds on decomposing lettuce leaves placed in the water. After a week, the aquarist can feed the fry newly hatched brine shrimp.
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