The best environment for any fish is one that closely matches its natural home conditions. Most aquarium fish are native to warm tropical areas with flowing waters, so require an aerated aquarium with good water quality and temperatures ranging from 72 to 82 F. The Betta fish (Betta splendens) is an exception, as it is an air-breathing fish from shallow stagnant waters that can do well in a quart size or larger bowl without needing aeration. It does require good water quality and warm water temperature. Unfortunately, it is rather challenging to provide that kind of environment in a small bowl. However, it's not impossible to make a bowl a reasonable home for your Betta if you are willing to make the effort. In climates that are warm year-round, a Betta can do pretty well in a bowl; provided the owner changes the water regularly.
A Tropical Fish
Bettas come from tropical Southeast Asia, where the water is usually around 80 F year-round. If you live in a temperate climate, wintertime weather can present obstacles. Cold temperatures below 65 F can kill a Betta fish. They prefer to be in water temperatures of 75 to 82 F. Being subjected to long periods of cooler than optimal water temperature will stress the fish, rendering it far more susceptible to disease. Placing the bowl in a warmer location in the house will help, but the best option for those living in cold climates is to keep the fish in a heated aquarium.
Another option is to put a mini-heater in your bowl. Keep in mind that bowls are challenging when it comes to maintaining the proper temperature. It is easy to overheat, underheat or have wide variances in temperatures. Frequent large temperature swings can be as stressful as constantly low temperatures. If you choose to keep your Betta in a bowl and heat it with a mini-heater, make sure you use an aquarium thermometer to monitor the temperature closely.
Does a Betta Need a Plant to Eat?
Plants are great for Betta bowls or aquariums, as Bettas like to nestle among the leaves to rest; but not to eat! Although some report that Bettas will nibble on a plant for food, that is not true. Bettas require meaty foods and are not plant eaters in nature. Yes, if they have no other food available, they will nibble on the plants. However, plant matter is not the ideal food for them. You should feed a good quality flake or pelleted fish food, along with treats of live or frozen brine shrimp, or freeze-dried tubifex worms. They will even eat live wingless fruit flies.
If you have a plant in the Betta bowl, but sure it doesn't prevent the Betta from getting to the surface to breathe. Furthermore, it will be much easier to care for your Betta if there isn't a large plant in the way. If the bowl is large enough, a small live aquarium plant can be used, but make sure the plant doesn't block out the entire surface of the water. If adding a live plant in a bowl, be sure to use a substrate that will provide nutrients to support healthy live plant growth. A small plant in a small pot of substrate available in pet stores will suffice, and be easy to remove when doing routine maintenance.
Clean the Marbles
The glass marbles on the bottom of the bowl are okay and are easy to remove for cleaning. Keep in mind that food can and does fall under them, so be sure to clean them whenever you perform your regular water change. Do not allow leftover food to accumulate in the substrate.
Key Habitat Factors of the Betta
The key factors for keeping your Betta happy and healthy are: keep the water and bowl clean by performing regular water changes, feed your Betta a varied diet and avoid letting the water remain cool (below 75 F) for long periods of time. Your Betta’s appearance and behavior is a good way to measure how he is feeling. A healthy Betta will be colorful, have a healthy appetite and is active and interested in what is going on around him. A listless, inactive Betta that has a poor appetite and/or frayed fins is a red flag that something is wrong in the environment.
Betta Fish Care. Adelphi University.
Sipauba-Tavares, LH., Appoloni, AM., Fernandes, JBK., Millan, RN. Feed of Siamese Fighting FIsh, Betta Splendens, (Rega, 1910) In Open Pond: Live and Formulated Diets. Brazilian Journal of Biology, 76,2, 2016, doi:10.1590/1519-6984.11514