FERTILIZATION: During spawning, the male and female betta join in what is known as an embrace where they curl their bodies together, aligning their reproductive organs together, under the bubblenest. The female deposits the eggs from her ovipositor. At the moment the eggs fall, the male releases milt (containing sperm) to fertilize them.
EGG: Betta fish eggs incubate approximately 24 – 36 hours inside the bubble nest.
FRY: Baby fish are called fry. Some definitions of fish fry say that fish are only referred to as a fry until their yolk sacks have been fully absorbed. After that stage, many species are referred to as fingerlings. Betta fish are almost never referred to as fingerlings. It is very common to hear breeders refer to their young bettas as fry until they have reached at least 6 weeks old and have grown significantly. Once hatched, the betta fry will stay in their bubble nest for another 3 days, approximately.
FREE-SWIMMING: An important milestone for young betta fry is when they reach their free-swimming stage. After they have absorbed their yolk sack they begin to swim on their own (hence, free-swimming stage) and venture away from the bubble nest.
LABYRINTH ORGAN DEVELOPMENT: Betta fry use their gills to extract oxygen from the water until while they continue to develop. At 3 – 6 weeks of age the labyrinth organ is fully functional. Bettas will use this special adaptation, in addition to their gills, to breathe air directly from the atmosphere. Betta splendens will continue to use this lung-like organ for the remainder of their lives.
JUVENILE: Young, fully developed bettas that have not yet reached sexual maturity are referred to as juvenile or adolescent bettas.
SEXUAL MATURITY: Betta splendens reach sexual maturity at approximately 3 months of age.
ADULT: Once sexually mature, a betta is considered an adult. They may not be completely full grown, and many continue to grow up to 1 year of age.
LIFE SPAN & DEVELOPMENT: Adult bettas continue to experience many physical changes throughout their life. Bettas may develop color changes or markings (e.g. marbling) that can vary from subtle to significant. Older bettas may develop light-colored, grey or white scales under the head that hobbyists refer to as a betta beard or bearding. Older bettas sometimes develop a dull color or loss of their natural sheen and may get ragged or tattered fins. With good genes and a healthy environment a betta’s natural life span is 3 – 4 years. Some bettas have been known to live for 5 years. Claims of bettas living longer than 6 years have been made but not confirmed.