Momchil

Hi, My name is Momchil and I'm the author of the cited article about Nitrate Poisoning in fish. I registered an account just to reply to this thread. @Coronal Mass Ejection Carl , thank you for your comments! I respect people who do their own research. Though there are still many unknowns in our hobby, there are some things that are now widely accepted practices because of scientific evidence. Therefore I'd have to kindly disgree with you (not looking for an argument, just want to clear things up if you'd allow me). Ok, here it goes... "The numbers from that article are whack. Below 2 ppm for reef aquariums? People are dosing nitrate well beyond that in reef tanks." It's true that SOME people dose Nitrate to improve the coloration of their corals. However, no more than 2 ppm of Nitrate are needed to maintain a beautiful reef, or you start getting overnutrification issues. I don't know if you've kept reef tanks, but what's important for keeping a successful reef aquarium is that you maintain a Redfield ratio of Nitrogen to Phosporus. Anyway, here's a study that discusses N:P ratios for coral health in detail: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5441187/ In that line of thoughts, there are plenty of reports where people with thriving reef tanks dose Nitrates to bring the total levels to between 2 and 4 ppm. In the article I mention 2 ppm of Nitrate, because going too far over that should come with significantly increased P levels if you don't want your corals bleached (as suggested in the scientific study I linked above). However, maintaining such large quantities of P also comes with algae issues, and other issues. - not something reef keepers consider a successful setup. Anyhow... "As evidence it cites a study where rainbow trout exhibit "side swimming" at 100 mg/L nitrate-N or 443 ppm nitrate and calls this swim bladder disorder." Side swimming is disturbed balance and buoyancy. It is extremely rare that a fish has buoyancy issues without a swim bladder malformation. Read on for that. "It's not the same thing." Here's a study suggesting otherwise: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4270422/ . Here's a citation from it: However, I'm saying "suggesting" because then they say this: The numbers provided in the study suggest that every side swimmer has swim bladder issues, but not every fish with swim bladder issues was swimming on its side. All in all, I could not find a study specifically saying that "side swimming = swim bladder disorder", but it's not that difficult to connect the dots, so to speak. Given the nature of Nitrate as a ion, how that affects osmoregulation in freshwater fish and how that in turn could lead to potential swim bladder disorder and therfore side swimming, I mean. Could you please provide a scientific study specifically saying that "side swimming =/= swim bladder disorder" (as you claimed)? Anyway, continuing: "The author of that study said certain variables such as potassium levels weren't controlled." Correct! They also did not control boron, if that matters for completely disproving the results of the study. "A few years later a similar but more thorough study is performed using Atlantic salmon and he noted that none of the side swimming or other abnormal behavior occurred. " I don't know how you assessed whether it was more thorough or not. I'm assuming this is the study you're referring to: https://www.sciencedirect.com/science/article/pii/S0144860917301231 In that, they started with 2016 fish in total and it lasted 8 months. The one I cited in Aquanswers started with 12300 fish and lasted 3 months. For the record, Potassium wasn't controlled in the study you refer as well (same as boron). Anyway, one reason for the different outcomes in the studies is obviously osmoregulation. Atlantic salmon, used in the study you cite as "more thorough", migrate from freshwater to saltwater for a couple of years and then back to freshwater. The study subjects were "post-smoltering" which means the Atlantic salmon already had their bodies change to adapt to high salinity. Obviously high salinity requires the exact opposite osmoregulation in fish than low salinity (look up the visual representation to get familiar with that). Nitrate, same as salt, is a ion. High Nitrate in the aquarium leads to more osmotic pressure for the fish. Impaired osmoregulation in freshwater fish leads to swollen organs, supressed swim bladder and kidney failure. The fish in the study I linked to in my article was Oncorhynchus mykiss. There are 2 types of Oncorhynchus mykiss (it's the same species but with different lifestyles): Rainbow trout - it spends the large majority, if not, all of its life in FRESHWATER Steelhead - it's born in freshwater but shortly after goes on to spend YEARS IN SALTWATER before returning to spawn in freshwater again. The authors of the study I linked to in my article refered to their study subjects as rainbow trout, which makes it extremely likely that the fish were adjusted to living in freshwater. Now let's get back to Nitrate sensitivity. As I point out in my article, saltwater fish are more resistant to high Nitrate and that's likely because their way of osmoregulation allows them to have less issues with water renetion and therefore swim bladder malformations from swelling of the organs. It is also well known among hobbyists that freshwater fish who naturally inhabit soft water are extremely sensitive to Nitrogen content (e.g. elevated Nitrate). That's likely because soft water has low levels of Total Dissolved Solids (TDS). For the record, Magnesium and Calcium are also ions and are the prevalent elements in what we call "hard water". It is also well known that Hard water fish can tolerate higher levels of Nitrate without showing illness (Guppies, mollies, platies, swordtails are all considered "hardy"). Following these thoughts, I think it's safe to conclude that high Nitrate is harmful to freshwater fish. All due respect, but I dare you to look after FRESHWATER fish in a tank that has 400 ppm of Nitrate. I'm confident that it would be a disaster at best. Anyway, moving on. "There's also no evidence for the claims that nitrate levels can cause spinal deformities. " That's my personal experience and observation. I discussed it with other experienced fish keepers who confirmed my observations. However, I did some digging just now and found that it has been observed by scientists as well - https://pubmed.ncbi.nlm.nih.gov/15173627/ From the study: And your last statement: "The nitrate LC50 for most fish species is in the thousands (4,000-8,000)" ...Apologies but source??? Also is this freshwater or saltwater fish? Though I doubt you'd find a source - If it's about saltwater fish, why cite it in a thread about freshwater aquariums? Anyway, I personally find it kind of annoying having to dig up scientific studies to back my every word, just because some person in a forum haven't heard of my website or what I said does not seem in line with whatever the current trend in the fish keeping hobby is. See, I have enormous respect for @Cory from Aquarium Co Op and what he does for this hobby. I don't think he should plug a scientific study for every three words he says in his videos. He's likely looked after hundreds of more aquariums than me and Coronal Mass Ejection Carl combined (though I did look after aquariums professionally for a short period of my career, but still). @Hobbit Unfortunately, many people would dismiss information just because they don't recognize the brand or website of the author. I do write for a certain type of audience and not everyone is into heavy and long research papers. This does not mean I don't do my research or don't have enough experience to provide valuable input on the subject. Don't forget that popularity is all about marketing. 🙂 Anyway that was it. Again, I do not look for an argument, but I wanted to clarify some things as the accusations demanded it IMO. Regards, Momchil