So you are going on a vacation for the weekend and you worry about leaving your fish alone. Here are some guidelines that can help you keep your Betta in perfect condition as you go on a weekend trip.
On Feeding. There are two relatively easy options for you. One is to find a fish sitter to care for your fish in your absence. The other option is to simply let your fish go unfed while you are gone. Bettas are capable of going for several days without a meal. In fact, healthy adult fish can go for a week or two without feeding. That doesn't mean you should routinely skip feedings, however they can safely be left without food over a long holiday weekend.
On Temperature. Temperature is only a concern if the room temperature is in danger of rising to dangerously high levels. Set your air conditioning to kick in if the room temperature rises above 30°C (86°F), and your fish will be quite comfortable while you are away. Your air conditioning should be set at no less than 23°C (73°F) or your fish will also be uncomfortable with the cold.
On Lighting. Lighting is easy to handle by purchasing a timer. No need to get a fancy one, just something that will turn the lights on and off once each day. That way the day/night cycle is standard.
On Water. Clean your bowl thoroughly just before you leave. You can also do a full water change this time. This will put toxins and wastes to a minimum, allowing water that will remain safe for the fish for about a week or two. That doesn't mean you should routinely do a full water change weekly, it is stressful to the fish. However, this stress is less threatening to the fish than not changing the water and leaving it for more than a week.
Fish Sitter. If you are going on an extended vacation (more than two weeks), you should either have someone tend your fish, or just bring the fish bowl with you. If you are going to get a fish sitter, the most important thing to impress upon your friend is that they should not overfeed your fish. Excess food will foul the water, and can prove lethal. Bettas will “beg” for more food when they are well fed, but should not be indulged. Also do store jars of pretreated water and train them to do weekly water changes.
Before Leaving. Check if the filter is working properly and examine your fish for signs of stress and disease. If you think that your fish is sick, it will need special care and should be brought to the nearest pet shop.