On top of that you crossbred a Veiltail and a Crowntail, so none of them will look proper if they were to survive. And again, you allowed fish bought from a dinky pet store like PetSmart, a store known for horribly breeding their Bettas. And while your fish are pretty, they are so very standard for a typical store bought fish.
Wow! 9 Proven Steps: How To Breed Betta Fish The Easy Way
Even in the fish tanks without a female fish, the male Betta will make the bubble nest because of its instincts. There is no specific time frame for them or period of cycle to observe. It is just known that they do it from time to time with their instincts that the atmosphere is compatible for breeding process.
Betta Fish Series - Breeding Betta Fish | The Aquarium Guide
This tail type is a very beautiful one, where the caudal fin is split in the middle, producing two caudal peduncles and what are referred to as tail lobes (fins). A true Double Tail should have an even split right to the body and have two caudal peduncles. The dorsal fin on a Double Tail is extended. Breeding Double Tails to Double Tails is a very risky cross, as this will produce fish with spinal deformities and short bodies due to the twin caudal peduncles. This tail type can sometimes be seen in combination with any of the Delta Tails and Half Moon bettas.
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