Betta splendens go through several unique and interesting lifecycle stages. Here is a brief introduction to the Lifecycle of the Siamese Fighting Fish – Betta splendens.
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.

One-Day Old Betta Fry, originally uploaded by adamszoo.

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Reader Interactions


  1. makala says:

    what i want to know is how old are my betta fish can someone please help me i just got them yesterday there not eating but i figured out why so no help for that but i just wanna know how old are they?

    • Christie F. says:

      You’d have to ask the fish store if they know exactly how old the fish were when they were sold to them by the breeder. Smaller Mom & Pop fish stores tend to know more about their stock than big pet stores like PetCo or PetSmart. The large stores probably won’t know. That said, most bettas are about 6 months when purchased and aren’t quite full sized. If yours is full sized, he is probably closer to a year old.

      • angel says:

        I would not get fish from petsmart they do not take all that much care into their fish. Yes they know what they talk about and have good tanks but when it comes to the fish..they all have ick.and now my big tank n my fish in there have ick and its really hard to get rid of it. I love small bussiness over a big one any day!….I’m a betta mommy as of yesterday and thank you for the info..very helpful=)

        • Pandaa says:

          I’ve gotten three of my bettas from Petsmart, and only one has popeye, and that is due to poor water quality (I took him in from my sister). So you could say that all of my bettas from Petsmart have been perfectly healthy. It may only be a stroke of luck, but I think that not all big chain stores treat their fish poorly.

    • coc says:

      they are about the age of 1 i now because all the betta fish in the store start the age at 1

      • Pandaa says:

        Not necessarily. I got one of my bettas very young, I’m guessing around 5-6 months of age. There is no specific age when they sell them.

    • carlos says:

      they are possybly young

  2. Mayra says:

    My betta fish (male) released a white net looking thing. Has anyone had a similar experience?

    • Christie F. says:

      Hmm. Not sure what you are describing. Can you elaborate?

    • Gigi says:

      It might be a bubble nest. How big is it?

  3. Brittaney says:

    My female betta has eggs, I think. She’s gotten rather fat and has the white spot that most pages say females get when carrying eggs. Approx. how long would the eggs be in her ? My male has a small bubble nest compared to the pictures I’ve seen, but he does have one built. And I just got the male so would he be old enough to actually fertalize the eggs ?

  4. Emily Grech says:

    I thought the information was very useful but I want to know more like what the fry eat or how long till you start feeding them. I have a male and I am going to get him a mate. I wanted to know if I should empty the bottom of the tank so he doesn’t loose the eggs to to the rocks. Thanks!

    • Christie F. says:

      Thanks Emily, We are working on expanding our articles to include information on rearing fry. More great info will be coming in the months ahead.

      • kara says:

        i have a male betta and he has built a nest. should i get him a female? how would i take care of the fry?? will the male or female try to kill the fry once they have hatched? please help!! thanks 🙂

  5. naveena says:

    i dont now why

  6. david says:

    my fry ia about 6 days old and i had remove the male today from the tanks. how should feed the young fry? they look to be swimming freely.

    • addyspena says:

      hi, go to the pet store and buy liquid for frys or artemia. that is their .food…. also put some plants for feeding on it, like, water lettuce and duckweed . You also have to cover them no light until a bit bigger.

  7. eric h h lin says:

    how do i indentified a male from a female after 2 months

  8. Amy says:

    What is the optimal age for breeding? Can you tell how old your fish is by its size? Will a 2 year old male breed?

  9. Sarimah Syed says:

    Hi Christie, may I know if the fry need an air pump to survive? Currently I have no air pump and filter in my tank where the breeding is taking place. Please advise. Thanks!

  10. Fracie says:

    I recently bought a male betta fish from walmart, & it just wont eat. I ran out of fish food so i fed it small bread crumbs & then when i got more fish food, it refused to eat any, but the bread crumbs. After two days, it refuses to eat anything! What should i do?
    My other problem is i have another fish, male. Its about a year, & its doing the same. It refuses to eat. All it does is float right below the top of the water, keeping its mouth above the water, breathing? I dont know what i should do with this fish either?

    • addyspena says:

      hello. you should stop feeding it for 1 or 2 days, don’t worry it won’t die, sometime they over eat. also find out what type of food were they feeding it maybe is different from the one you are giving it.. . they also do not like a heavy filter with noise . put plants like water lettuce , clean it water,.and if you have it in a lot of water reduce the level of water that way it dose not have to swim a lot to get to the surface for air.

  11. Bryana says:

    Hi, I just bought a crowntail from Wal-Mart and he is pretty small. I’m thinking he is a 5-7 months. Compared to my other 2 bettas, he is about half an inch skinnier, and is about 2 and a half inches long, while my other fish are about 3 and a half. How old do you think he is?

  12. Mike jabbs says:

    Hi- i have been breeding bettas for quite a while and heres whats worked very well for me:
    A) breed fish of the same size only. Bigger fish, regardless of sex can and usually will cause much physical damage to smaller ones as bettas courtship is naturally a rather violent affair by human standards. Death is not unheard of in improperly sized pairs.
    B) condition fish for at least 10 days prior feeding a rich, varied, nutritious diet of good quality flakes , frozen bloodworm, Betta pellet and live brineshrimp . Producing the eggs taxes the female and the male doesnt get fed fed until he’s removed from the breeding tank 4-5 days after the breeding. She is removed immediately afterwards and melafix or similar first aid treatment begins. He gets the same when he’s removed.
    C) use a 5gal. Bare bottom tank with 4.5 inches of aged water (ultimately from a mature cycled tank if possible .unsure what that means?’look it up) heated to 26-28° celsius. use a sponge filter that’s been “marinated ” in the dirty water from the mature tank for 3-5hrs so the beneficial bacteria in working as you Won’t be able to do any cleaning for probably 10 days after fry hatch. There should also be able a few live plants sitting on the bottom either in small pots or tied to driftwood . Javamoss or javaferns work best for giving females hiding spots during breeding and the fry feed on the zooaplankton for the first 2-3 days after leaving the bubblenest. Remove the male when fry have absorbed their yolks.

  13. Kiri says:

    How does their behaviour change when they are sexually mature?

  14. Lisa says:

    Will a male pick up eggs and deposit them in the nest one by one, or take as many as he can at one time then put them all in? Mine are going for it ATM and unsure if he’s just munching them or not?

  15. Gigi says:

    I have a betta that was sold to me as “baby betta.” It did not say the gender or age. I have had it for about 5 months, and it is only about 1 inch long not including fins. The fins are very short too. It has somewhat dull colors, and I can kind of see an egg spot. I just want to know some more about my fish. Can anyone help?

    • k says:

      She is female Betta

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