An overfed betta fish can show signs like a bloated belly, loss of appetite, and refusal to eat. Keep an eye on their behavior, as they may also become lethargic or show less interest in their surroundings. Uneaten food can also accumulate at the bottom of the tank. To prevent overfeeding, offer small amounts of food at a time, and only feed what your betta can consume in a few minutes. It's important to maintain a feeding schedule and not exceed the recommended amount of food. Providing a varied diet with high-quality pellets, frozen or live foods can also help promote healthy eating habits. Regular exercise in a spacious tank can also prevent obesity in betta fish.