Many marine aquarists dose their tank daily with a vitamin C supplement to boost their livestock's immune systems.
Vitamin C is an antioxidant (ascorbic acid) that positively affects the immune system of fishes and possibly some marine invertebrates. Vitamin C is naturally occurring in the marine environment (in seaweed, for example), and there is strong data from scientists and mariculture professionals, that dosing vitamin C has many positive effects on marine life. Some marine aquarists absolutely will not dose anything for which they cannot test, and while it is possible to test for vitamin C in the water, such tests are not very realistic for the average hobbyist.
How to Use Vitamin C
There are several vitamin C products on the market, such as Kent Marine’s Marine-C vitamin supplement. Because vitamin C is water soluble (vitamins are either water soluble or fat soluble) it is effective when dosed directly to the aquarium water. Fishes and coral then take in the vitamin during normal respiration. Vitamin C can also be used to soak food before feeding. Soaking food in vitamin C may be a more effective vehicle for the vitamin as long as the target animal(s) ingests the food.
Don’t Fix What Ain’t Broke
Some aquarists believe that adding vitamin C to your tank just because someone said it was good for your livestock is foolish and that you should only ever do something that has a direct and specific purpose. Generally speaking, this is good advice, although there is little to no anecdotal evidence of dosing vitamin C being harmful to livestock. It is known that insufficient levels of vitamin C are linked to spinal abnormalities and hemorrhaging, so if you see these signs, you may want to consider dosing vitamin C.
Dosage Amount
The recommended dosage for Kent Marine’s Marine-C is 1 ml daily for every 50 gallons of aquarium water daily. Even though most vitamin C products intended for aquarium use are buffered, it is wise to monitor your system’s pH, as even the buffered supplement is somewhat acidic.
Vitamin C can also be used less regularly to address specific issues such as head and lateral line erosion, bacterial and parasitic infestations, and wounds. It can be dosed to the entire tank or used in a hospital tank. Vitamin C is also great for corals that have been recently fragmented for propagation purposes.
Not a Wonder Drug
Vitamin C is not a wonder vitamin, a silver bullet or a great new discovery. Is dosing vitamin C right for everyone? No more so than choosing to keep zoanthids or Banngai Cardinalfish. It's all about informing yourself through research, listening to others' opinions and applying what you learn to the unique characteristics of your system. For some marine aquarists, that has led them to dose things like vitamin C and vodka. For others, it will lead them to dose nothing. The only mandate is that you document what you do, observe the results and share your experience with other hobbyists.
