Why is my female betta fish small? Is her growth normal for her age?

Bettas, both male and female, are considered "full grown" at about 7 months of age. There may be some growth until a year of age with most specimens measuring 2-2.5 inches in length. Freddie looks to be in fine form in the images provided. Be sure to maintain water quality and temperature. Bettas do best between 78F and 80F. For water changes, use only aged or conditioned water that is temperature matched to prevent stress or shock.

While she is a baby, you can feed her twice a day. Only feed as much as she can eat in a minute or two. If you feed too much the feed will fall to the ground and then contaminate the water.Later, when she is grown up you can change to feeding her once a day. Your fish figured out that you feed her when you come near the tank, So it is fairly normal for her to beg.

The best guess would be an adult. Unless you know the hatch date, it is difficult to be more specific. Adult Bettas are about 3 inches long. They reach this length anywhere between 7 and 12 months of age. His eyes are dark, his color is good and his fins are long. He's at least a year old. That would be my best "educated guess" based on the images provided.

Make sure there are plenty of plants and other hiding areas for her. She may be more stressed than the other and it may take more time for her to adjust. Also they all have personalities and some are more “outgoing” than others. She may always be more timid. Best of luck and enjoy them!

Beta fish lay eggs and she would need a male to then fertilize those eggs after she lays them. Breeding betas can be very work intensive. Here is a link with great information: fishkeepingworld.com/breeding-betta-fish/ As the babies get bigger, they can graduate to larger food. The babies will mature and need to be separated around 3 months of age. The females can stay together but all the males will need to be separated. Breeding betas requires a lot of tanks/space. I recommend to connect with a local aquarium store and find out if anyone has first hand knowledge. I hope this helps and please feel free to post any additional questions.

This is difficult to determine exactly from the picture you posted. There seems to be a mild swelling which could be completely normal at this stage (especially if not other signs are present). Please complete your question adding other pictures (one from above would be quite helpful) and describing if other signs are present or not to receive more answers from us.

She doesn't seem very small to me from looking at the pictures, but pictures can be misleading, so I'd have to see her in-person to really tell. Stunted growth essentially happens for four different reasons: 1) Hormone deficiency - would be a very small cat (almost kitten-sized). 2) Genetics 3) Disease - such a liver shunt, or high parasite load 4) Lack of proper nutrition at a young age In the pictures, Diamond Nilo appears to be well proportioned, has a good coat and is generally not sickly appearing. This information actually goes a long way to saying that it's likely just genetics -- she is just a smaller breed. If she had any of the other conditions, then it would be more obvious by now, because she would have deformities, or continually showing signs of illness. Without knowing her whole history, it's difficult to know how healthy she is, but if you are not noticing any other problems with her, then I would not worry about getting bad news at the vet's office. I hope that helps and all is well with Diamond Nilo.