Velvet Information and Symptoms
Velvet is probably the second most common Betta ailment next to fin rot. Velvet is generally caused by unstable temperatures, or temperatures that are too cool for the betta to comfortably deal with (generally anything that falls below 72 degrees for long periods of time). Poor water quality can also increase a Betta’s chances of contracting velvet. Velvet is the number one killer of very young Betta fry, so if you are a breeder, familiarize yourself with this disease so that you can diagnose it before it gets out of control in your fry tanks.
Velvet is a parasitic infection which attacks the Betta’s slime coat. It generally infects the head and gill area first, so that by the time it is noticeable, the infection is pretty well established. The main indicator that your Betta has Velvet is a copper or rust colored dusting over the betta’s body, normally beginning at the head, but it will very quickly spread over the entire body if not treated. Bettas that have Velvet will usually be very lethargic, have clamped fins, and may not be interested in eating. It is very important to treat Velvet as soon as it becomes apparent.
If your Betta shows signs of Velvet, it is best to isolate him for treatment. If you are dealing with a Velvet outbreak in a fry tank, it is best to treat the entire tank. Do a complete water change if your betta is in his own container, and a 30-40% water change if it is in a community/fry tank and you must treat in the tank. Adding aquarium or rock salt (dissolve before introducing to the tank) will help until stronger medications can be purchased, and can be used in conjunction with medication. Many of the same medications that are useful in the treatment of Ick are also good Velvet treatments. Aquarisol is my personal favorite medication for Velvet, but Maracide, Malachite Green, and Coppersafe (as well as other copper-based medications) can be used. Be aware that stong copper-based medications can eventually lead to poisoning, so water should be changed frequently after treatment to remove the medications, unless you are treating in a container that gets 100% water changes. Also be aware that some of these medications are harmful to plants and invertibrates, so do your homework before treating in tanks containing plants and invertibrates.
Once medications have been added, if at all possible, increase the tank temperature to 82-84 degrees F. This will speed the life cycle of Velvet and allow the medications to kill it faster. If your treatment container is too small to heat, allow the medications to work at their own rate but try to place the container in a warm area of the house. Keeping the tank dark will also help to destroy Velvet, as Velvet is actually a parasitic algae and requires a bit of light to survive. Keep an eye out for secondary opporunistic infections, as fish that contract Velvet are already in a weakened, vulnerable state.
Stable (warm) temperatures and clean water are the two major things you can do to prevent Velvet in adult Bettas. In Betta fry tanks, or with adult Bettas that seem especially prone to Velvet infections, adding about 1 teaspoon per gallon of dissolved aquarium/rock salt can help prevent Velvet from setting in (when used in conjunction with stable temperatures and regular water changes). Aquarisol can also be used according to the directions on the bottle as a preventative, which I especially recommend for Betta fry tanks in which the fry are under one month of age.