Why did my betta die after a water change? Is my other betta at risk?

Cold water can affect activity in fish. Bettas are tropical fish and do best between 78 F and 80 F. Check the water chemistry also. You can use a home test kit, such as the API Master Kit, or submit a water sample for testing. The local Petco may do this for free or for a small fee. Aim for an absence (0 ppm) of ammonia and nitrites with nitrates at 20ppm or less. Perform a partial water change if necessary to stabilize chemistry and/or to improve water quality. Use only conditioned water that is temperature matched to prevent stress or shock. Diet can influence color, so it is possible this is partly to blame for the color change. There are diets that can be fed to enhance colors.

Check the water temperature first. Bettas are tropical fish and do best between 78 F and 80 F. Next, check water quality. This can be done by using a home test kit or by submitting a water sample for testing. The local pet store may do this for free or for a small fee. Aim for an absence ( 0 ppm) of ammonia and nitrites with nitrates at 20 ppm or less. Perform partial water changes if necessary. Use only conditioned water that is temperature matched to prevent stress or shock. Offer an appropriate diet as well. Bettas are carnivorous, so make sure the flake or pellet is not mainly vegetable matter. Hikari makes a great Betta diet in pellet form. You can also offer blood worms, shrimp or Daphnia to add variety to the diet.

He is "old" for a Betta. Check the water chemistry and temperature. You can use a home test kit or submit a water sample for testing. The local Petco may do this for free or for a small fee. Aim for an absence (0 ppm) of ammonia and nitrites with nitrates at 20ppm or less. Perform partial water changes to stabilize chemistry and/or to improve water quality. Use only conditioned water that is temperature matched to prevent stress or shock. Bettas do best between 78 F and 80 F. The cloudy eyes may be due to infection. Maintaining pristine water quality will help, but you may need a broad spectrum antibiotic as well. Look in the aquarium section of the local Petco for medication. Follow label directions carefully and remove the carbon filter insert during treatment if indicated. Even with treatment, there may be permanent damage to the eyes if the condition has been chronic. The "laying down" is sometimes seen even in healthy fish. They may choose to lay on gravel or the broad leaf of a plant. It may also indicate infection or injury though. If hebisbhavibg difficulty reaching the surface, decrease the water level to make it easier. Bettas need to surface occasionally to get some air.

When performing water changes it is recommended to change about 15-25 %of the water. His helps keep some of the good bacteria in the water as well as decreases dramatic temperature changes which can cause significant stress on the body. I suspect that it is the temp change that is hard in him, however if a dechlorinator was not used in the water then that could be problematic as well. If you feel that is the case please Add a dechlorinator. I hope he improves!

I recommend to start with having the water tested. Many times this is offered by the pet store. If all the fish have passed away, the culprit is most often poor water quality, a disease or the tank not being properly maintained for the species of fish. I do not recommend to get more fish until you know the water conditions are correct and that you know the environment (temperature...etc) is appropriate for the species of fish you want to have. I hope this helps.

As long as you are properly setting up the environment for your new fish, not stressing him out too much, and making sure he is happy and healthy, he shouldn't pass away at a certain time of day. A google search can give you a myriad of information about how to care for your betta, however most do best in an actual tank with a proper filter and heater to keep things warm and fresh, a lid to keep active bettas from jumping out and becoming injured, and for males, no other bettas or aggressive fish in the tank. If you're unsure if your tank environment is safe, most pet stores will test water samples for free and point you in the direction of any changes you need to make.

Check water chemistry first. Use a home test kit or submit a water sample for testing. Aim for an absence (0 ppm) of ammonia and nitrites with nitrates at 20 ppm or less. Perform a partial water change to stabilize water chemistry and/or to improve water quality. Use only conditioned water that is temperature matched to prevent further stress or shock. Bettas do best between 78 F and 80 F. By your description, the issue may be swim bladder disease. This can be caused by infection (bacterial or parasites) or constipation. Maintain water quality as described above. Fast the fish for 3 days then resume feeding bits of cooked and shelled green peas. This will help with constipation. If this doesn't help. you can get a broad spectrum antibiotic from the local pet store. Look in the aquarium section. Follow label directions carefully and remove the carbon filter insert during treatment.