| Young Betta | Old Betta | |
| 1. Size | Smaller and more slender. They are often less than 2 inches (5 cm) long, and their fins may appear shorter and less elaborate. | Usually be between 2 to 3 inches (5-7.5 cm) long. As Betta fish mature, they also develop longer, more flowing fins, especially in males. Older Bettas might have slightly bulkier bodies as they fill out. |
| 2. Coloration | The colors might not be as vibrant or developed. They can be more translucent or dull in appearance. | Their color often becomes more intense. Mature males are particularly known for their bright and striking colors, such as red, blue, or iridescent hues. |
| 3. Fin shape and length | Generally have shorter, less defined fins, and they may not yet have the extravagant tail shapes (like crown tails, veil tails, or half moons) that adult Bettas are known for. | Adult Betta fish, particularly males, will have long, flowing fins, and the tail shape will be more pronounced. The fins might also show some wear and tear as the fish gets older, especially if it's been in the tank for a long time. |
| 4.Behavior | Tend to be more active and playful. They may dart around the tank quickly and explore their environment with high energy. | My become less active and spend more time resting. They can also become less territorial and more passive with age, although this can vary based on the individual personality of the fish. |
| 5. Body Condition | Wll be sleek and smooth, with no visible signs of aging | As Bettas age, you may notice signs like slight body deformities or a thinner, more sunken body, especially if they are nearing the end of their lifespan. Older Bettas may also develop cloudy eyes or a slower metabolism. |
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6. Gills |
A young Betta’s gills are typically bright red or pink and fully functional. | Older Bettas may have gills that are slightly darker or less vibrant, and may show signs of wear or infection over time. |
