Vitamin C and Aquarium Livestock Nutrition by Kenneth WingerterWhen it comes to animal diets, there is not necessarily a close correlation between the normal amount of intake of certain components and the degree to which they are required for normal growth and metabolism. Take for example ascorbic acid (widely known as vitamin C). This compound makes up a freaking miniscule fraction of most animals’ diets, yet they will surely become ill or even die without it. Plants (including algae) can synthesize this substance on their own; however, many aquatic animals (numerous crustaceans, most fishes, etc.) are incapable of vitamin C synthesis and therefore rely on it traveling up the food chain. This makes intermediates in the food chain (such as copepods) quite important over the larger scale of food webs. While the nutritional importance of vitamin C is widely recognized, few aquarists consider it much when developing a feeding regimen for their captive animals. This article serves as an overview of ascorbic acid and tosses out some suggestions for ensuring that it is present in your animals’ diets. Vitamin C for life Most organisms require ascorbic acid for reason or another. This vitamin is involved in a wide variety of metabolic processes. It is an antioxidant. It aids in detoxification. It improves iron absorption. And, it promotes healthy bone growth. In crustaceans (which have a considerable ascorbic acid requirement), vitamin C deficiency is associated with complications during molting, improper collagen growth and darkened lesions over the exoskeleton. In fish, deficiency is associated with poor skin health, scoliosis and an overall lack of fitness. Deficiencies can easily occur in captivity where captive diets are too often geared towards lower cost and greater convenience rather than nutritional content. Even where some foods might have some vitamin C content to begin with, it can be rapidly lost as it degraded by various actors during processing, storage and handling. These actors include moisture, oxygen, heat and even light. Exposure to any of these can render ascorbic acid into a number of biologically inactive substances. Thus, the ascorbic acid content listed in the “guaranteed analysis” portion of the ingredients section on a product label does not necessarily add up in the product itself. One thing some aquarists do to compensate for the rapid degradation of this vitamin is simply add some extra quantity. Sure, because animals cannot store vitamin C, any excess is lost as waste. But, fortunately, it is pretty hard to overdose on it. Perhaps at extremely high doses it can crystalize in the kidney and cause issues. But there is for the most part a minimal risk of overdosing this vitamin. Fishkeepers are advised to include approximately 2,000 mg/kg vitamin C in fish feed. Shrimp farmers use a bit more, often using it at a rate of approximately 2,500 mg/kg. Curious and adventurous individuals have experimented with adding vitamin C to the water. The vitamin was once believed by some aquarists to be a cure for head and lateral line erosion and was even added directly to the aquarium water in an effort to effect a cure for the malady; however, as it turns out, the effect this treatment had was seriously reducing the system’s pH. On the hand, one study demonstrated that brine shrimp are somehow capable of taking up ascorbic acid directly from the water. Moving on Since true plants aren’t abundant in most marine habitats, it is algae (both microalgae and macroalgae) that are responsible for introducing vitamin C into marine food webs. So it’s pretty easy to see how an herbivore such as a tang would introduce ascorbic acid into its diet. But how about a fish like a mandarin that never, ever eats vegetable material? To understand this, let’s consider what mandarins do eat: Pods! Perhaps with very few exceptions, copepods all eat algae at some point of their life cycle (at least while eating phyto as planktonic larvae). Generally, copepods (and certainly the copepod species we seed into our reef tanks) will happily accept microalgae throughout their entire lives. As these little crustaceans graze on phyto and benthic microalgae, they essentially fill their guts with vitamin C; microalgae is loaded with vitamin C (0.11-1.62% dry weight!). When “gut loaded” in this way, they ultimately become a source of vitamin C for the mandarin. The dietary importance of vitamin C, as well as its high susceptibility for degradation, make it a very good idea to add it via live sources. For your larger algae-eaters such as rabbitfish, sea urchins, etc., you can use algal material that is discarded from a planted refugium. Sea lettuce and red ogo are fantastic choices of macros for this purpose. When it comes to other animals… well, it can get a little more complicated. Because it is difficult to grow phyto directly in a properly filtered aquarium, aquarists often need to add phyto (such as OceanMagik). This phyto (and the vitamin C contained therein) is consumed in different ways. Corals, sponges, tube worms and other filter-feeders can consume it directly. Same with copepod larvae. But it is adult copepods that, through grazing of benthic algae, transfer the vitamin up the food chain. It can get into the tank’s food web through multiple means; what’s important in the end is that your animals all have the intake they require how regular growth and development, as well as to resist ailments. While it is always wise to keep close tabs on our lighting, water quality, etc., it might also be a good idea to ensure our creatures are provided with ample vitamin C through quality prepared foods and (better yet) through fresh live algal-based foods. References [1] Hoff, Frank H. and Terry W. Snell. Plankton Culture Manual. 6th ed. Dade City, FL: Florida Aqua Farms, Inc., 1987. [2] Campbell Neil A. and Jane B. Reece. Biology. 6th ed. San Francisco, CA: Benjamin Cummings, 2002. [3] Hemdal, Jay F. Advanced Marine Aquarium Techniques. Neptune City, NJ: T.F.H. Publications, 2006.
ryorzins says January 31, 2022 at 1:10 pm I’ve never supplemented my go-to fish food with vitamin -C. Something I should consider adding after reading this informative article. Reply
billy.t.williams12 says February 28, 2022 at 2:24 pm I know what you mean, I have never even heard of supplementing with vitamins unless it is a very special fish that required a special diet. Reply
Daniel Olguin says June 3, 2022 at 9:51 am fish food with vitamin C Something I should consider adding after reading this. Reply
Carlos Matias-Tejada says March 9, 2023 at 4:25 pm i wonder if the frozen raw foods we cna purchase already contain a good amount of vitamin c from the minerals or byproducts of what they add in the foods.. Reply
ryorzins says January 31, 2022 at 1:13 pm I’ve never thought about adding vitamin C to my fishes diet although I do feed a quality food. Perhaps I should consider using a vitamin supplement after reading this informative article. Reply
ryorzins says January 31, 2022 at 1:15 pm I think I should consider a vitamin-C additive to the quality fish food I feed. Very informative article. Reply
Wendy says March 19, 2022 at 11:54 am I’ve never thought to add vit c, I will have to do some more research. Thanks for the great read Reply
Brian Veach says January 31, 2022 at 2:57 pm Very cool article about how the food chain works. You don’t think about it often, but every creature in the tank has a role to play in keeping other creatures healthy. Reply
Channon says November 11, 2023 at 3:11 pm Algae offers the most diverse source of copepods if you ask me Reply
bundler says January 31, 2022 at 6:25 pm I will aspire to providing more sources of ascorbic acid! Reply
anatolek says February 5, 2022 at 7:57 am So how long until we see a video on YouTube about how to put a slice of orange in a refugium 🙂 Reply
chief300 says February 7, 2022 at 3:34 pm I have never thought about vitamin C , something to concerder Reply
sam says February 7, 2022 at 10:55 pm I’m trying to cure 2 hippo tangs of HLLE. one is really bad off. They are recovering but the small one will always be maimed. Reply
Dallas T. says February 8, 2022 at 9:45 am I have never purposely supplemented Vitamin C. I will have to investigate this further. Reply
tbrown3589 says February 8, 2022 at 6:50 pm It’s also useful because it’s a natural dechlorinator, but that requires adding it to the water, not the food. Reply
brittneymlasley says February 8, 2022 at 7:19 pm #Algaebarn is great at educating the saltwater community! Reply
alenm826 says February 10, 2022 at 5:20 pm There are pros and con to using vitamin c in my opinion. Had it set up on a dose but the tube would clog up every time, it was due to the fact that I needed to shake the bottle every couple of days. Over all it’s a good benefit to the reef, first hand experience here Reply
James Bradshaw says February 14, 2022 at 3:50 pm I stopped using phytoplankton when my supply crashed during Texas’ winter storm last year and thought I wouldn’t need it again but I’m going to order more and start up the system again asap! Reply
gerrynator4 says February 14, 2022 at 11:40 pm I didn’t really think of vitamin C in reef tanks, but it does make sense. Reply
gerrynator4 says February 14, 2022 at 11:40 pm I didn’t really think of vitamin C in reef tanks, but it does make sense. Reply
gerrynator4 says February 14, 2022 at 11:40 pm I didn’t really think of vitamin C in reef tanks, but it does make sense. Reply
Beth S says February 15, 2022 at 11:56 am Look forward to more interesting posts on the micro nutrients. I used to be able to get fresh ocean water for my tank, and it was so amazing. Settling for the salt and additions has been a struggle ever since that became impossible Reply
Alan Biddle says February 21, 2022 at 5:15 pm Interesting. Never thought about vitamin c and my fish. Reply
jason_lifted35 says February 28, 2022 at 10:13 pm Very good article, tons of info. Vita Chem all the way. Reply
kevin.t1680 says March 28, 2022 at 3:06 pm think I should consider a vitamin-C additive to the quality fish food I feed. Reply
Jeff Carr says April 5, 2022 at 3:40 am I usually feed high quality foods. This is new to me. May try it out. Reply
Andrew Pellegrino says April 6, 2022 at 12:00 pm I find that vitamin C is one of the most important minerals in the world! Reply
sarah.sandpoint says April 11, 2022 at 8:24 pm Have not heard much about C – we use the ocean magik so hopefully that will cover it. Reply
sarah.sandpoint says April 11, 2022 at 8:24 pm Have not heard much about C – we use the ocean magik so hopefully that will cover it. Reply
blackadonai says April 14, 2022 at 9:06 am I love articles like this. Always makes me feel better about all the work I’ve been putting into setting up systems to grow live foods Reply
Kathleen Ryan says May 30, 2022 at 2:13 pm My crabs have basically mowed down a lot of the macroalgae in my tank except for sea lettuce — maybe they were looking for Vitamin C? Reply
ernie.alvarez0325 says May 30, 2022 at 4:52 pm Wow, interesting reading! Always learning something new! Reply
markwdunlap88 says June 6, 2022 at 2:56 pm I am normally very specific regarding my fish and their diet but I’ve never tried Vitamin C. Great article and very helpful information Reply
crplcarott says June 8, 2022 at 12:27 pm Interesting article. I will keep up with the pods and Ocean Magic. Reply
Griffin says June 8, 2022 at 8:52 pm my food is all diy seafood and selcon so im hoping im good Reply
Andrea says June 14, 2022 at 5:49 am I never realized how important Vitamin C is in the reef tank! I mean we need it… so guess they do too! Reply
sclarke_o says June 16, 2022 at 6:50 am I always relied on proven food brands and variety but I’ve not really go as far as supplementing Reply
sclarke_o says June 16, 2022 at 6:55 am I always relied on proven food brands and variety food type that contain some of the needed nutrients but I’ve not really go as far as supplementing Specific nutrients like vitamin C … good food for thought now …. Reply
Alan J. Tomasetti says July 8, 2022 at 5:02 pm Curious to know how much vitamin C is in Selcon and other major brands out there… Reply
Christopher Hooks says July 12, 2022 at 12:31 pm Never used this might be worth giving it a try Reply
Jessica Rico says October 24, 2022 at 6:24 am I’ve been looking into this and I’m going to give it a whirl! Reply
KiltedReefer says November 5, 2022 at 2:40 pm Food for thought? Vitamin C supplements I think so. Reply
Yueqi Wang says November 18, 2022 at 6:14 pm I used Vitamin C to help my clownfish when they had digestive issues (white long poop), it worked well! Reply
Pete Tellers says November 29, 2022 at 4:24 pm I never knew fish couldn’t process vitamin C… interesting. Reply
Manuel Urrutia says January 28, 2023 at 12:29 pm It is interesting to see the numbers behind what some commercial shrimp farmers use to supplement their livestock to life the best possible life once outside of their care. Reply
Nicholas Aguiar says September 13, 2023 at 4:59 pm ngl i didn’t know that vitamin C in a tank was a thing. i’ll probably slide some food that has it now lol. i want my fish to be happy. Reply
Jeffrey Miller says October 22, 2023 at 7:20 pm Learn something new all the time. Definitely going to keep this in mind. Reply
professorcanswanky says November 12, 2023 at 9:36 am Very interesting read. I’ve never really thought of dosing vitamins alone. Definitely something I think more people should talk about. Reply
Amber Breedlove says December 1, 2023 at 7:11 am WOW THANK YOU SO MUCH FOR THE WONDERFUL INSIGHT !!!! Reply
Brendan Thomas says December 5, 2023 at 5:24 pm Great information, I have seen vitamin c as an additive in some food Reply
Matthew Hubble says March 21, 2024 at 7:42 pm I always add selcon, garlic and vitachem to my feedings! Reply
Joseph Uttlinger says July 10, 2024 at 9:18 pm First I’ve ever heard of supplementing vitamin C into the aquarium. Something to consider. Reply
Michael Valle says January 19, 2025 at 8:48 pm Well considering how much we invest in our tanks, adding another supplement that we are sorta familiar with, makes sense. It’s all relative to how much can you really invest in your tank. I’d try it. Reply
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