Betta fry hatch exceptionally small, and the first month is a feeding ladder: each food must fit mouths that grow a little every few days. Warm still water, humid air above the surface, gentle waste removal, and food offered in the right order matter more than any single product or gadget.
Prepare the Tank and Hand Over From the Father
Start your infusoria culture well before spawning, since a culture takes days to bloom and a hungry first week cannot be replayed. Spawn the pair in a shallow tank filled to about 12 to 15 centimetres (roughly 5 to 6 inches), with a floating plant or leaf for the nest and a tight lid. The male builds a bubble nest, tends the eggs, and returns fallen fry to the nest for the first days. Eggs typically hatch within about a day to a day and a half, and fry hang tail-down under the nest while they absorb a small yolk sac. Once fry swim horizontally and scatter from the nest, at about three to four days old, net the father out gently and return him to his own tank. His care ends there, and a hungry male left in place will begin eating fry.
Feed Infusoria Through the First Week
Free-swimming fry need microscopic food from the first day they level out. Infusoria cultured in advance, or a liquid fry food used sparingly, suits mouths that cannot yet manage anything visible to the eye. Offer tiny amounts three or four times a day, watching for fry gathered at the surface film with full, rounded bellies. Keep light gentle and long enough for fry to hunt, and avoid pouring large volumes of culture water into the fry tank in one go.
A magnifier held against the glass helps you confirm that fry are feeding, since a first-week betta is little more than eyes and a tail, and an empty belly is hard to judge with the naked eye alone.
Graduate to Baby Brine Shrimp and Then Dry Food
From about day five to seven, fry that are hunting actively can usually manage newly hatched baby brine shrimp, and orange bellies after a feed confirm the food fits. Hatch small batches daily so shrimp stay newly hatched and small, and keep infusoria going alongside for a few days because a batch always contains slower growers. During weeks two and three, add microworms and keep baby brine shrimp as the main feed. During weeks three and four, introduce finely crushed dry fry food in small amounts alongside live food, reducing live feeds only as fry take the dry food readily. A mixed ladder keeps runts fed while stronger fry move ahead.
Hold Water, Air, and Cleanliness Steady All Month
Keep the tank warm and stable, and top up evaporation with matched water rather than performing large changes in the first fortnight. From the second week, siphon the floor gently with airline tubing daily and replace the small volume removed with matched water, a little at a time. The lid matters beyond splashing: young bettas develop a breathing organ during weeks two to four, and they must gulp warm humid air at the surface, so cold dry room air above the water is a genuine risk during that window. Note the feed ladder, hatch dates for shrimp batches, and daily siphon duties in KinsLe through Care Teams, so a second pair of hands can follow the same sequence without guessing what the fry ate last.