the size of it's fins and body
Adult betta fish, specifically the males, will grow in the majority of their fins as juveniles. When you see bettas in the stores for sale, they are typically around 2 years old already since it takes time for their full finnage to appear.
It's all in the tail. the males is larger and longer and the females is shorter.
A betta normally only lives 2-3 years, so it would be around 70 years old in "betta years".
Betta fish grow paler and less active when they are sick or old.
ya
A nine month old betta is already full grown, so yes.
their colors dull. for example, instead of bright purples and blues, they would be a dull lavender or baby blue.
No betta fish are carnivores.
other Betta fish and the bigger fish.
Betta fish do not eat fish.
Well, if you love your Betta fish, then it should live by itself. But if you add another Betta to your current Betta fish's tank, then they will start a fight because Betta Fish are Siamese fighting fish and if one Betta is in contact of another Betta, the possible reason would be a fight between them two.
A betta is a fish of the species Betta, especially Betta splendens, commonly known as the Siamese fighting fish.