Bettas kept in small cups at big box stores suffer a variety of illnesses as a result of the poor and stressful conditions they are kept in. Not only do they suffer as a result of poor water quality, but the shipment, often aggressive handling and processing, bright lights, loud noises, and frequent tapping or moving of the cups, contribute to their condition by weakening them and making them more susceptible to illness. 

The number one illness that affects these fish is ammonia and/or nitrite poisoning. This poisoning can cause a WIDE variety of symptoms and adds additional stress that further heightens their propensity for severe illnesses. Any time you rescue a cup betta, your number one priority should be collecting and testing a water sample from the cup. Ammonia and nitrite are the most important to test. I often only do ammonia, because if ammonia is high, nitrite probably is too, and we don’t really need exact numbers for everything here. If ammonia or nitrite is near or over 1ppm, the fish should be treated for nitrogen poisoning. When I get home with a new rescue, I typically will get a water sample first, then immediately put the fish into a cup with fresh water, then test the water and decide the next steps from there. 

To treat the nitrogen poisoning you will need methylene blue and a container to make a bath in. The dosage I recommend is 20 drops per 1 gallon of water, bringing it to 6ppm methylene blue. This dosage is safe for a 30 minute bath. This can be repeated as needed. I like to give a day or two minimum between baths to allow the fish time to heal. 

Alternatively, some methylene blue manufacturers recommend a 50ppm solution to be used as a 10 second bath for nitrogen poisoning. This will work as well, but is not my preferred method, and timing needs to be strict so it’s a bit trickier to accomplish safely. 

Once you have tested the water and treated the fish for poisoning or determined it was not needed, the fish can be placed in an appropriately sized tank and allowed to recover for several days. The vast majority of the time, these fish only require a warm cycled tank to fully recover past this point and most will show massive improvement in 2-5 days. 

If the fish is having trouble swimming, you can keep them in their cup with clean water and float it in the tank. The cup can be submerged several times a day to refresh the water and keep water quality high. Lowing the water level or using another small container is also a good option. 

I will only do more than this in rare circumstances, like if the fish has obvious signs of major infection, fin rot close to the body, parasites, or other severe issues. Most buoyancy issues will resolve with time in good conditions. If the fish has not improved in 2-5 days or continues to decline, treatment should be started according to symptoms only unless doing preventative parasite treatments, which are safe(see our guide on parasites). Antibiotics should not be used preventatively and without indication. Improper antibiotic usage contributes to antibiotic resistant infections and makes our fish harder to treat. 

If you are doing a fish-in cycle with your newly rescued betta, keeping an eye on the parameters and doing water changes is even more important than usual. Since your rescued fish is likely already affected by the ammonia and nitrite, great caution needs to be taken to not re-expose them. If you don’t already have the API freshwater master test kit, you’ll need to get one and test the water daily. I would also recommend ordering Fritz turbo start or Fritz zyme 7 to add beneficial bacteria to the tank and speed up the cycling process. For more information on tank set up, cycling, and fish-in cycles, see our guide. 

Common complications of ammonia and nitrite poisoning:

-Gill hyperplasia (picture 6&7, see our guide for more info) 

-Swim bladder issues(difficulty swimming up, back half of fish seems to be point down, you may even see the swim bladder swollen at the back end of the body)

-Loss of equilibrium(can’t swim straight, bumping into things, etc)

-Floating and inability to swim down(often caused by bacterial or constipation issues in the abdomen that allow gasses to build up)

-Fin and body rot

-Pop eye and cloudy eye