Bubble nest

Nest built by some fish and frog species to protect their eggs

Bubble nests, also called foam nests, are created by some fish and frog species as floating masses of bubbles blown with an oral secretion, saliva bubbles, and occasionally aquatic plants. Fish that build and guard bubble nests are known as aphrophils. Aphrophils include gouramis and the synbranchid eel Monopterus alba in Asia, Microctenopoma (Anabantidae), Polycentropsis (Nandidae), and Hepsetus odoe in Africa, and callichthyines and the electric eel in South America. Most, if not all, fish that construct floating bubble nests live in tropical, oxygen-depleted standing waters. Osphronemidae, containing the bettas and gouramis, are the most commonly recognized family of bubble nest makers, though some members of that family mouthbrood instead. The nests are constructed as a place for fertilized eggs to be deposited while incubating and guarded by one or both parents until the fry hatch.

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